1
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Xia T, Wu W, Wu X, Qu J, Chen Y. Cobalt-Catalyzed Enantioselective Reductive α-Chloro-Carbonyl Addition of Ketimine to Construct the β-Tertiary Amino Acid Analogues. Angew Chem Int Ed Engl 2024; 63:e202318991. [PMID: 38252658 DOI: 10.1002/anie.202318991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 01/21/2024] [Accepted: 01/22/2024] [Indexed: 01/24/2024]
Abstract
β-Tertiary amino acid derivatives constitute one of the most frequently occurring units in natural products and bioactive molecules. However, the efficient asymmetric synthesis of this motif still remains a significant challenge. Herein, we disclose a cobalt-catalyzed enantioselective reductive addition reaction of ketimine using α-chloro carbonyl compound as a radical precursor, providing expedient access to a diverse array of enantioenriched β-quaternary amino acid analogues. This protocol exhibits outstanding enantioselectivity and broad substrate scope with excellent functional group tolerance. Preliminary mechanism studies rule out the possibility of Reformatsky-type addition and confirm the involvement of radical species in stereoselective addition process. The synthetic utility has been demonstrated through the rapid assembly of iterative amino acid units and oligopeptide, showcasing its versatile platform for late-stage modification of drug candidates.
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Affiliation(s)
- Tingting Xia
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Wenwen Wu
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Xianqing Wu
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Jingping Qu
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Yifeng Chen
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
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2
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Fu H, Hyster TK. From Ground-State to Excited-State Activation Modes: Flavin-Dependent "Ene"-Reductases Catalyzed Non-natural Radical Reactions. Acc Chem Res 2024; 57:1446-1457. [PMID: 38603772 DOI: 10.1021/acs.accounts.4c00129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
Enzymes are desired catalysts for chemical synthesis, because they can be engineered to provide unparalleled levels of efficiency and selectivity. Yet, despite the astonishing array of reactions catalyzed by natural enzymes, many reactivity patterns found in small molecule catalysts have no counterpart in the living world. With a detailed understanding of the mechanisms utilized by small molecule catalysts, we can identify existing enzymes with the potential to catalyze reactions that are currently unknown in nature. Over the past eight years, our group has demonstrated that flavin-dependent "ene"-reductases (EREDs) can catalyze various radical-mediated reactions with unparalleled levels of selectivity, solving long-standing challenges in asymmetric synthesis.This Account presents our development of EREDs as general catalysts for asymmetric radical reactions. While we have developed multiple mechanisms for generating radicals within protein active sites, this account will focus on examples where flavin mononucleotide hydroquinone (FMNhq) serves as an electron transfer radical initiator. While our initial mechanistic hypotheses were rooted in electron-transfer-based radical initiation mechanisms commonly used by synthetic organic chemists, we ultimately uncovered emergent mechanisms of radical initiation that are unique to the protein active site. We will begin by covering intramolecular reactions and discussing how the protein activates the substrate for reduction by altering the redox-potential of alkyl halides and templating the charge transfer complex between the substrate and flavin-cofactor. Protein engineering has been used to modify the fundamental photophysics of these reactions, highlighting the opportunity to tune these systems further by using directed evolution. This section highlights the range of coupling partners and radical termination mechanisms available to intramolecular reactions.The next section will focus on intermolecular reactions and the role of enzyme-templated ternary charge transfer complexes among the cofactor, alkyl halide, and coupling partner in gating electron transfer to ensure that it only occurs when both substrates are bound within the protein active site. We will highlight the synthetic applications available to this activation mode, including olefin hydroalkylation, carbohydroxylation, arene functionalization, and nitronate alkylation. This section also discusses how the protein can favor mechanistic steps that are elusive in solution for the asymmetric reductive coupling of alkyl halides and nitroalkanes. We are aware of several recent EREDs-catalyzed photoenzymatic transformations from other groups. We will discuss results from these papers in the context of understanding the nuances of radical initiation with various substrates.These biocatalytic asymmetric radical reactions often complement the state-of-the-art small-molecule-catalyzed reactions, making EREDs a valuable addition to a chemist's synthetic toolbox. Moreover, the underlying principles studied with these systems are potentially operative with other cofactor-dependent proteins, opening the door to different types of enzyme-catalyzed radical reactions. We anticipate that this Account will serve as a guide and inspire broad interest in repurposing existing enzymes to access new transformations.
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Affiliation(s)
- Haigen Fu
- NHC Key Laboratory of Biotechnology for Microbial Drugs, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Todd K Hyster
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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3
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Ju S, Li D, Mai BK, Liu X, Vallota-Eastman A, Wu J, Valentine DL, Liu P, Yang Y. Stereodivergent photobiocatalytic radical cyclization through the repurposing and directed evolution of fatty acid photodecarboxylases. Nat Chem 2024:10.1038/s41557-024-01494-0. [PMID: 38632367 DOI: 10.1038/s41557-024-01494-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 02/28/2024] [Indexed: 04/19/2024]
Abstract
Despite their intriguing photophysical and photochemical activities, naturally occurring photoenzymes have not yet been repurposed for new-to-nature activities. Here we engineered fatty acid photodecarboxylases to catalyse unnatural photoredox radical C-C bond formation by leveraging the strongly oxidizing excited-state flavoquinone cofactor. Through genome mining, rational engineering and directed evolution, we developed a panel of radical photocyclases to facilitate decarboxylative radical cyclization with excellent chemo-, enantio- and diastereoselectivities. Our high-throughput experimental workflow allowed for the directed evolution of fatty acid photodecarboxylases. An orthogonal set of radical photocyclases was engineered to access all four possible stereoisomers of the stereochemical dyad, affording fully diastereo- and enantiodivergent biotransformations in asymmetric radical biocatalysis. Molecular dynamics simulations show that our evolved radical photocyclases allow near-attack conformations to be easily accessed, enabling chemoselective radical cyclization. The development of stereoselective radical photocyclases provides unnatural C-C-bond-forming activities in natural photoenzyme families, which can be used to tame the stereochemistry of free-radical-mediated reactions.
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Affiliation(s)
- Shuyun Ju
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Dian Li
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Binh Khanh Mai
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Xin Liu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Alec Vallota-Eastman
- Interdepartmental Graduate Program for Marine Science, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Jianping Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - David L Valentine
- Marine Science Institute, University of California Santa Barbara, Santa Barbara, CA, USA
- Department of Earth Science, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Yang Yang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA.
- Biomolecular Science and Engineering (BMSE) Program, University of California Santa Barbara, Santa Barbara, CA, USA.
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4
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Qin Z, Zhou Y, Li Z, Höhne M, Bornscheuer UT, Wu S. Production of Biobased Ethylbenzene by Cascade Biocatalysis with an Engineered Photodecarboxylase. Angew Chem Int Ed Engl 2024; 63:e202314566. [PMID: 37947487 DOI: 10.1002/anie.202314566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/06/2023] [Accepted: 11/10/2023] [Indexed: 11/12/2023]
Abstract
Production of commodity chemicals, such as benzene, toluene, ethylbenzene, and xylenes (BTEX), from renewable resources is key for a sustainable society. Biocatalysis enables one-pot multistep transformation of bioresources under mild conditions, yet it is often limited to biochemicals. Herein, we developed a non-natural three-enzyme cascade for one-pot conversion of biobased l-phenylalanine into ethylbenzene. The key rate-limiting photodecarboxylase was subjected to structure-guided semirational engineering, and a triple mutant CvFAP(Y466T/P460A/G462I) was obtained with a 6.3-fold higher productivity. With this improved photodecarboxylase, an optimized two-cell sequential process was developed to convert l-phenylalanine into ethylbenzene with 82 % conversion. The cascade reaction was integrated with fermentation to achieve the one-pot bioproduction of ethylbenzene from biobased glycerol, demonstrating the potential of cascade biocatalysis plus enzyme engineering for the production of biobased commodity chemicals.
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Affiliation(s)
- Zhaoyang Qin
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Street, Wuhan, 430070, P. R. China
| | - Yi Zhou
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Street, Wuhan, 430070, P. R. China
| | - Zhi Li
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Matthias Höhne
- Institute of Chemistry, Technische Universität Berlin, Müller-Breslau-Str. 10, 10623, Berlin, Germany
| | - Uwe T Bornscheuer
- Department of Biotechnology and Enzyme Catalysis, Institute of Biochemistry, University of Greifswald, Felix Hausdorff-Str. 4, 17489, Greifswald, Germany
| | - Shuke Wu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Street, Wuhan, 430070, P. R. China
- Department of Biotechnology and Enzyme Catalysis, Institute of Biochemistry, University of Greifswald, Felix Hausdorff-Str. 4, 17489, Greifswald, Germany
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5
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Shi Q, Kang XW, Liu Z, Sakthivel P, Aman H, Chang R, Yan X, Pang Y, Dai S, Ding B, Ye J. Single-Electron Oxidation-Initiated Enantioselective Hydrosulfonylation of Olefins Enabled by Photoenzymatic Catalysis. J Am Chem Soc 2024; 146:2748-2756. [PMID: 38214454 DOI: 10.1021/jacs.3c12513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Controlling the enantioselectivity of hydrogen atom transfer (HAT) reactions has been a long-standing synthetic challenge. While recent advances on photoenzymatic catalysis have demonstrated the great potential of non-natural photoenzymes, all of the transformations are initiated by single-electron reduction of the substrate, with only one notable exception. Herein, we report an oxidation-initiated photoenzymatic enantioselective hydrosulfonylation of olefins using a novel mutant of gluconobacter ene-reductase (GluER-W100F-W342F). Compared to known photoenzymatic systems, our approach does not rely on the formation of an electron donor-acceptor complex between the substrates and enzyme cofactor and simplifies the reaction system by obviating the addition of a cofactor regeneration mixture. More importantly, the GluER variant exhibits high reactivity and enantioselectivity and a broad substrate scope. Mechanistic studies support the proposed oxidation-initiated mechanism and reveal that a tyrosine-mediated HAT process is involved.
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Affiliation(s)
- Qinglong Shi
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiu-Wen Kang
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhiyong Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory on Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Pandaram Sakthivel
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hasil Aman
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Rui Chang
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaoyu Yan
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yubing Pang
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shaobo Dai
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory on Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Bei Ding
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Juntao Ye
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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6
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Singh PP, Sinha S, Nainwal P, Singh PK, Srivastava V. Novel applications of photobiocatalysts in chemical transformations. RSC Adv 2024; 14:2590-2601. [PMID: 38226143 PMCID: PMC10788709 DOI: 10.1039/d3ra07371h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 12/28/2023] [Indexed: 01/17/2024] Open
Abstract
Photocatalysis has proven to be an effective approach for the production of reactive intermediates under moderate reaction conditions. The possibility for the green synthesis of high-value compounds using the synergy of photocatalysis and biocatalysis, benefiting from the selectivity of enzymes and the reactivity of photocatalysts, has drawn growing interest. Mechanistic investigations, substrate analyses, and photobiocatalytic chemical transformations will all be incorporated in this review. We seek to shed light on upcoming synthetic opportunities in the field by precisely describing mechanistically unique techniques in photobiocatalytic chemistry.
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Affiliation(s)
- Praveen P Singh
- Department of Chemistry, United College of Engineering & Research Prayagraj U. P.-211010 India
| | - Surabhi Sinha
- Department of Chemistry, United College of Engineering & Research Prayagraj U. P.-211010 India
| | - Pankaj Nainwal
- School of Pharmacy, Graphic Era Hill University Dehradun Uttarakhand India
| | - Pravin K Singh
- Department of Chemistry, CMP Degree College, University of Allahabad Prayagraj U. P.-211002 India
| | - Vishal Srivastava
- Department of Chemistry, CMP Degree College, University of Allahabad Prayagraj U. P.-211002 India
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7
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Capone M, Dell’Orletta G, Nicholls BT, Scholes GD, Hyster TK, Aschi M, Daidone I. Evidence of a Distinctive Enantioselective Binding Mode for the Photoinduced Radical Cyclization of α-Chloroamides in Ene-Reductases. ACS Catal 2023; 13:15310-15321. [PMID: 38058601 PMCID: PMC10696551 DOI: 10.1021/acscatal.3c03934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/06/2023] [Accepted: 10/30/2023] [Indexed: 12/08/2023]
Abstract
We demonstrate here through molecular simulations and mutational studies the origin of the enantioselectivity in the photoinduced radical cyclization of α-chloroacetamides catalyzed by ene-reductases, in particular the Gluconobacter oxidans ene-reductase and the Old Yellow Enzyme 1, which show opposite enantioselectivity. Our results reveal that neither the π-facial selectivity model nor a protein-induced selective stabilization of the transition states is able to explain the enantioselectivity of the radical cyclization in the studied flavoenzymes. We propose a new enantioinduction scenario according to which enantioselectivity is indeed controlled by transition-state stability; however, the relative stability of the prochiral transition states is not determined by direct interaction with the protein but is rather dependent on an inherent degree of freedom within the substrate itself. This intrinsic degree of freedom, distinct from the traditional π-facial exposure mode, can be controlled by the substrate conformational selection upon binding to the enzyme.
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Affiliation(s)
- Matteo Capone
- Department
of Physical and Chemical Sciences, University
of L’Aquila, via
Vetoio (Coppito 1), L’Aquila 67010, Italy
| | - Gianluca Dell’Orletta
- Department
of Physical and Chemical Sciences, University
of L’Aquila, via
Vetoio (Coppito 1), L’Aquila 67010, Italy
| | - Bryce T. Nicholls
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14853, United States
| | - Gregory D. Scholes
- Department
of Chemistry, Frick Laboratory, Princeton
University, Princeton, New Jersey 08544, United States
| | - Todd K. Hyster
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14853, United States
| | - Massimiliano Aschi
- Department
of Physical and Chemical Sciences, University
of L’Aquila, via
Vetoio (Coppito 1), L’Aquila 67010, Italy
| | - Isabella Daidone
- Department
of Physical and Chemical Sciences, University
of L’Aquila, via
Vetoio (Coppito 1), L’Aquila 67010, Italy
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8
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Chen H, Fu W, Yang Y. P450-catalyzed atom transfer radical cyclization. Methods Enzymol 2023; 693:31-49. [PMID: 37977735 DOI: 10.1016/bs.mie.2023.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Cytochromes P450 have been extensively studied for both fundamental enzymology and biotechnological applications. Over the past decade, by taking inspiration from synthetic organic chemistry, new classes of P450-catalyzed reactions that were not previously encountered in the biological world have been developed to address challenging problems in organic chemistry and asymmetric catalysis. In particular, by repurposing and evolving P450 enzymes, stereoselective biocatalytic atom transfer radical cyclization (ATRC) was developed as a new means to impose stereocontrol over transient free radical intermediates. In this chapter, we describe the detailed experimental protocol for the directed evolution of P450 atom transfer radical cyclases. We also delineate protocols for analytical and preparative scale biocatalytic atom transfer radical cyclization processes. These methods will find application in the development of new P450-catalyzed radical reactions, as well as other synthetically useful processes.
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Affiliation(s)
- Heyu Chen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, United States
| | - Wenzhen Fu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, United States
| | - Yang Yang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, United States; Biomolecular Science and Engineering (BMSE) Program, University of California, Santa Barbara, CA, United States.
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9
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Püllmann P, Homann D, Karl TA, König B, Weissenborn MJ. Light-Controlled Biocatalysis by Unspecific Peroxygenases with Genetically Encoded Photosensitizers. Angew Chem Int Ed Engl 2023; 62:e202307897. [PMID: 37597259 DOI: 10.1002/anie.202307897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/16/2023] [Accepted: 08/16/2023] [Indexed: 08/21/2023]
Abstract
Fungal unspecific peroxygenases (UPOs) have gained substantial attention for their versatile oxyfunctionalization chemistry paired with impressive catalytic capabilities. A major drawback, however, remains their sensitivity towards their co-substrate hydrogen peroxide, necessitating the use of smart in situ hydrogen peroxide generation methods to enable efficient catalysis setups. Herein, we introduce flavin-containing protein photosensitizers as a new general tool for light-controlled in situ hydrogen peroxide production. By genetically fusing flavin binding fluorescent proteins and UPOs, we have created two virtually self-sufficient photo-enzymes (PhotUPO). Subsequent testing of a versatile substrate panel with the two divergent PhotUPOs revealed two stereoselective conversions. The catalytic performance of the fusion protein was optimized through enzyme and substrate loading variation, enabling up to 24300 turnover numbers (TONs) for the sulfoxidation of methyl phenyl sulfide. The PhotUPO concept was upscaled to a 100 mg substrate preparative scale, enabling the extraction of enantiomerically pure alcohol products.
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Affiliation(s)
- Pascal Püllmann
- Research Group Bioorganic Chemistry, Leibniz Institute for Plant Biochemistry, Weinberg 3, 06120, Halle (Saale), Germany
- Present address: Molecular Design and Engineering, Bayer AG, Aprather Weg 18 A, 42113, Wuppertal, Germany
| | - Dominik Homann
- Research Group Bioorganic Chemistry, Leibniz Institute for Plant Biochemistry, Weinberg 3, 06120, Halle (Saale), Germany
- Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Tobias A Karl
- Institute for Organic Chemistry, University of Regensburg, Universitätstr. 31, 93053, Regensburg, Germany
| | - Burkhard König
- Institute for Organic Chemistry, University of Regensburg, Universitätstr. 31, 93053, Regensburg, Germany
| | - Martin J Weissenborn
- Research Group Bioorganic Chemistry, Leibniz Institute for Plant Biochemistry, Weinberg 3, 06120, Halle (Saale), Germany
- Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, Weinbergweg 22, 06120, Halle (Saale), Germany
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10
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Abstract
The ability to site-selectively modify equivalent functional groups in a molecule has the potential to streamline syntheses and increase product yields by lowering step counts. Enzymes catalyze site-selective transformations throughout primary and secondary metabolism, but leveraging this capability for non-native substrates and reactions requires a detailed understanding of the potential and limitations of enzyme catalysis and how these bounds can be extended by protein engineering. In this review, we discuss representative examples of site-selective enzyme catalysis involving functional group manipulation and C-H bond functionalization. We include illustrative examples of native catalysis, but our focus is on cases involving non-native substrates and reactions often using engineered enzymes. We then discuss the use of these enzymes for chemoenzymatic transformations and target-oriented synthesis and conclude with a survey of tools and techniques that could expand the scope of non-native site-selective enzyme catalysis.
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Affiliation(s)
- Dibyendu Mondal
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Harrison M Snodgrass
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Christian A Gomez
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Jared C Lewis
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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11
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Page CG, Cao J, Oblinsky DG, MacMillan SN, Dahagam S, Lloyd RM, Charnock SJ, Scholes GD, Hyster TK. Regioselective Radical Alkylation of Arenes Using Evolved Photoenzymes. J Am Chem Soc 2023; 145:11866-11874. [PMID: 37199445 PMCID: PMC10859869 DOI: 10.1021/jacs.3c03607] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Substituted arenes are ubiquitous in molecules with medicinal functions, making their synthesis a critical consideration when designing synthetic routes. Regioselective C-H functionalization reactions are attractive for preparing alkylated arenes; however, the selectivity of existing methods is modest and primarily governed by the substrate's electronic properties. Here, we demonstrate a biocatalyst-controlled method for the regioselective alkylation of electron-rich and electron-deficient heteroarenes. Starting from an unselective "ene"-reductase (ERED) (GluER-T36A), we evolved a variant that selectively alkylates the C4 position of indole, an elusive position using prior technologies. Mechanistic studies across the evolutionary series indicate that changes to the protein active site alter the electronic character of the charge transfer (CT) complex responsible for radical formation. This resulted in a variant with a significant degree of ground-state CT in the CT complex. Mechanistic studies on a C2-selective ERED suggest that the evolution of GluER-T36A helps disfavor a competing mechanistic pathway. Additional protein engineering campaigns were carried out for a C8-selective quinoline alkylation. This study highlights the opportunity to use enzymes for regioselective radical reactions, where small molecule catalysts struggle to alter selectivity.
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Affiliation(s)
- Claire G. Page
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Jingzhe Cao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Daniel G. Oblinsky
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Samantha N. MacMillan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Shiva Dahagam
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Ruth M. Lloyd
- Prozomix. Building 4, West End Ind. Estate, Haltwhistle, Northumberland, NE49 9HN (UK)
| | - Simon J. Charnock
- Prozomix. Building 4, West End Ind. Estate, Haltwhistle, Northumberland, NE49 9HN (UK)
| | - Gregory D. Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Todd K. Hyster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
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12
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Xu W, Zhong H, Wu Y, Qin Y, Jiao L, Sha M, Su R, Tang Y, Zheng L, Hu L, Zhang S, Beckman SP, Gu W, Yang Y, Guo S, Zhu C. Photoexcited Ru single-atomic sites for efficient biomimetic redox catalysis. Proc Natl Acad Sci U S A 2023; 120:e2220315120. [PMID: 37186847 PMCID: PMC10214184 DOI: 10.1073/pnas.2220315120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 03/28/2023] [Indexed: 05/17/2023] Open
Abstract
The unsatisfactory catalytic activity of nanozymes owing to their inefficient electron transfer (ET) is the major challenge in biomimetic catalysis-related biomedical applications. Inspired by the photoelectron transfers in natural photoenzymes, we herein report a photonanozyme of single-atom Ru anchored on metal-organic frameworks (UiO-67-Ru) for achieving photoenhanced peroxidase (POD)-like activity. We demonstrate that the atomically dispersed Ru sites can realize high photoelectric conversion efficiency, superior POD-like activity (7.0-fold photoactivity enhancement relative to that of UiO-67), and good catalytic specificity. Both in situ experiments and theoretical calculations reveal that photoelectrons follow the cofactor-mediated ET process of enzymes to promote the production of active intermediates and the release of products, demonstrating more favorable thermodynamics and kinetics in H2O2 reduction. Taking advantage of the unique interaction of the Zr-O-P bond, we establish a UiO-67-Ru-based immunoassay platform for the photoenhanced detection of organophosphorus pesticides.
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Affiliation(s)
- Weiqing Xu
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan430079, P.R. China
| | - Hong Zhong
- School of Mechanical and Materials Engineering, Washington State University, Pullman, WA99164
| | - Yu Wu
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan430079, P.R. China
| | - Ying Qin
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan430079, P.R. China
| | - Lei Jiao
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan430079, P.R. China
| | - Meng Sha
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan430079, P.R. China
| | - Rina Su
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan430079, P.R. China
| | - Yinjun Tang
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan430079, P.R. China
| | - Lirong Zheng
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing100049, P.R. China
| | - Liuyong Hu
- School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan430205, P.R. China
| | - Shipeng Zhang
- School of Materials Science and Engineering, Peking University, Beijing100871, P.R. China
| | - Scott P. Beckman
- School of Mechanical and Materials Engineering, Washington State University, Pullman, WA99164
| | - Wenling Gu
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan430079, P.R. China
| | - Yong Yang
- State Key Laboratory of Solidification Processing, Center of Advanced Lubrication and Seal Materials, Northwestern Polytechnical University, Xi’an710072, P.R. China
| | - Shaojun Guo
- School of Materials Science and Engineering, Peking University, Beijing100871, P.R. China
| | - Chengzhou Zhu
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan430079, P.R. China
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13
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Emmanuel MA, Bender SG, Bilodeau C, Carceller JM, DeHovitz JS, Fu H, Liu Y, Nicholls BT, Ouyang Y, Page CG, Qiao T, Raps FC, Sorigué DR, Sun SZ, Turek-Herman J, Ye Y, Rivas-Souchet A, Cao J, Hyster TK. Photobiocatalytic Strategies for Organic Synthesis. Chem Rev 2023; 123:5459-5520. [PMID: 37115521 PMCID: PMC10905417 DOI: 10.1021/acs.chemrev.2c00767] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Biocatalysis has revolutionized chemical synthesis, providing sustainable methods for preparing various organic molecules. In enzyme-mediated organic synthesis, most reactions involve molecules operating from their ground states. Over the past 25 years, there has been an increased interest in enzymatic processes that utilize electronically excited states accessed through photoexcitation. These photobiocatalytic processes involve a diverse array of reaction mechanisms that are complementary to one another. This comprehensive review will describe the state-of-the-art strategies in photobiocatalysis for organic synthesis until December 2022. Apart from reviewing the relevant literature, a central goal of this review is to delineate the mechanistic differences between the general strategies employed in the field. We will organize this review based on the relationship between the photochemical step and the enzymatic transformations. The review will include mechanistic studies, substrate scopes, and protein optimization strategies. By clearly defining mechanistically-distinct strategies in photobiocatalytic chemistry, we hope to illuminate future synthetic opportunities in the area.
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Affiliation(s)
- Megan A Emmanuel
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Sophie G Bender
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Catherine Bilodeau
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Jose M Carceller
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
- Institute of Chemical Technology (ITQ), Universitat Politècnica de València, València 46022,Spain
| | - Jacob S DeHovitz
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Haigen Fu
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Yi Liu
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Bryce T Nicholls
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Yao Ouyang
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Claire G Page
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Tianzhang Qiao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Felix C Raps
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Damien R Sorigué
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
- Aix-Marseille University, CEA, CNRS, Institute of Biosciences and Biotechnologies, BIAM Cadarache, 13108 Saint-Paul-lez-Durance, France
| | - Shang-Zheng Sun
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Joshua Turek-Herman
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Yuxuan Ye
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Ariadna Rivas-Souchet
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Jingzhe Cao
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Todd K Hyster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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14
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Speirs M, Hardman SJO, Iorgu AI, Johannissen LO, Heyes DJ, Scrutton NS, Sazanovich IV, Hay S. Photoinduced Electron Transfer from a 1,4,5,6-Tetrahydro Nicotinamide Adenine Dinucleotide (Phosphate) Analogue to Oxidized Flavin in an Ene-Reductase Flavoenzyme. J Phys Chem Lett 2023; 14:3236-3242. [PMID: 36972502 PMCID: PMC10084465 DOI: 10.1021/acs.jpclett.3c00176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/23/2023] [Indexed: 06/18/2023]
Abstract
Recent reports have described the use of ene-reductase flavoenzymes to catalyze non-natural photochemical reactions. These studies have focused on using reduced flavoenzyme, yet oxidized flavins have superior light harvesting properties. In a binary complex of the oxidized ene-reductase pentaerythritol tetranitrate reductase with the nonreactive nicotinamide coenzyme analogs 1,4,5,6-tetrahydro NAD(P)H, visible photoexcitation of the flavin mononucleotide (FMN) leads to one-electron transfer from the NAD(P)H4 to FMN, generating a NAD(P)H4 cation radical and anionic FMN semiquinone. This electron transfer occurs in ∼1 ps and appears to kinetically outcompete reductive quenching from aromatic residues in the active site. Time-resolved infrared measurements show that relaxation processes appear to be largely localized on the FMN and the charge-separated state is short-lived, with relaxation, presumably via back electron transfer, occurring over ∼3-30 ps. While this demonstrates the potential for non-natural photoactivity, useful photocatalysis will likely require longer-lived excited states, which may be accessible by enzyme engineering and/or a judicious choice of substrate.
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Affiliation(s)
- Magnus Speirs
- Manchester
Institute of Biotechnology and Department of Chemistry, Faculty of
Science and Engineering, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Samantha J. O. Hardman
- Manchester
Institute of Biotechnology and Department of Chemistry, Faculty of
Science and Engineering, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Andreea I. Iorgu
- Manchester
Institute of Biotechnology and Department of Chemistry, Faculty of
Science and Engineering, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Linus O. Johannissen
- Manchester
Institute of Biotechnology and Department of Chemistry, Faculty of
Science and Engineering, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Derren J. Heyes
- Manchester
Institute of Biotechnology and Department of Chemistry, Faculty of
Science and Engineering, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Nigel S. Scrutton
- Manchester
Institute of Biotechnology and Department of Chemistry, Faculty of
Science and Engineering, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Igor V. Sazanovich
- Central
Laser Facility, Research Complex at Harwell, Science and Technology Facilities
Council, Harwell Oxford, Didcot OX11 0QX, United Kingdom
| | - Sam Hay
- Manchester
Institute of Biotechnology and Department of Chemistry, Faculty of
Science and Engineering, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
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15
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Using enzymes to tame nitrogen-centred radicals for enantioselective hydroamination. Nat Chem 2023; 15:206-212. [PMID: 36376390 DOI: 10.1038/s41557-022-01083-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 10/02/2022] [Indexed: 11/16/2022]
Abstract
The formation of C-N bonds-of great importance to the pharmaceutical industry-can be facilitated enzymatically using nucleophilic and nitrene transfer mechanisms. However, neither natural nor engineered enzymes are known to generate and control nitrogen-centred radicals, which serve as valuable species for C-N bond formation. Here we use flavin-dependent 'ene'-reductases with an exogenous photoredox catalyst to selectively generate amidyl radicals within the protein active site. These enzymes are engineered through directed evolution to catalyse 5-exo, 6-endo, 7-endo, 8-endo, and intermolecular hydroamination reactions with high levels of enantioselectivity. Mechanistic studies suggest that radical initiation occurs via an enzyme-gated mechanism, where the protein thermodynamically activates the substrate for reduction by the photocatalyst. Molecular dynamics studies indicate that the enzymes bind substrates using non-canonical binding interactions, which may serve as a handle to further manipulate reactivity. This approach demonstrates the versatility of these enzymes for controlling the reactivity of high-energy radical intermediates and highlights the opportunity for synergistic catalyst strategies to unlock previously inaccessible enzymatic functions.
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16
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Fu H, Qiao T, Carceller JM, MacMillan SN, Hyster TK. Asymmetric C-Alkylation of Nitroalkanes via Enzymatic Photoredox Catalysis. J Am Chem Soc 2023; 145:787-793. [PMID: 36608280 DOI: 10.1021/jacs.2c12197] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Tertiary nitroalkanes and the corresponding α-tertiary amines represent important motifs in bioactive molecules and natural products. The C-alkylation of secondary nitroalkanes with electrophiles is a straightforward strategy for constructing tertiary nitroalkanes; however, controlling the stereoselectivity of this type of reaction remains challenging. Here, we report a highly chemo- and stereoselective C-alkylation of nitroalkanes with alkyl halides catalyzed by an engineered flavin-dependent "ene"-reductase (ERED). Directed evolution of the old yellow enzyme from Geobacillus kaustophilus provided a triple mutant, GkOYE-G7, capable of synthesizing tertiary nitroalkanes in high yield and enantioselectivity. Mechanistic studies indicate that the excitation of an enzyme-templated charge-transfer complex formed between the substrates and cofactor is responsible for radical initiation. Moreover, a single-enzyme two-mechanism cascade reaction was developed to prepare tertiary nitroalkanes from simple nitroalkenes, highlighting the potential to use one enzyme for two mechanistically distinct reactions.
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Affiliation(s)
- Haigen Fu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Tianzhang Qiao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Jose M Carceller
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States.,Institute of Chemical Technology (ITQ), Universitat Politècnica de València, València 46022, Spain
| | - Samantha N MacMillan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Todd K Hyster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
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17
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Collaborative catalysis for solar biosynthesis. TRENDS IN CHEMISTRY 2022. [DOI: 10.1016/j.trechm.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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18
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Yu Y, Lin RD, Yao Y, Shi ML, Lu WF, Wang N, Yu XQ. Development of a Metal- and Oxidant-Free Enzyme–Photocatalyst Hybrid System for Highly Efficient C-3 Acylation Reactions of Indoles with Aldehydes. ACS Catal 2022. [DOI: 10.1021/acscatal.2c03080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yuan Yu
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Ru-De Lin
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Yao Yao
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Ming-Liang Shi
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Wei-Fan Lu
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Na Wang
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Xiao-Qi Yu
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
- Department of Chemistry, Xihua University, Chengdu 610039, P. R. China
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19
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Hirschi S, Ward TR, Meier WP, Müller DJ, Fotiadis D. Synthetic Biology: Bottom-Up Assembly of Molecular Systems. Chem Rev 2022; 122:16294-16328. [PMID: 36179355 DOI: 10.1021/acs.chemrev.2c00339] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The bottom-up assembly of biological and chemical components opens exciting opportunities to engineer artificial vesicular systems for applications with previously unmet requirements. The modular combination of scaffolds and functional building blocks enables the engineering of complex systems with biomimetic or new-to-nature functionalities. Inspired by the compartmentalized organization of cells and organelles, lipid or polymer vesicles are widely used as model membrane systems to investigate the translocation of solutes and the transduction of signals by membrane proteins. The bottom-up assembly and functionalization of such artificial compartments enables full control over their composition and can thus provide specifically optimized environments for synthetic biological processes. This review aims to inspire future endeavors by providing a diverse toolbox of molecular modules, engineering methodologies, and different approaches to assemble artificial vesicular systems. Important technical and practical aspects are addressed and selected applications are presented, highlighting particular achievements and limitations of the bottom-up approach. Complementing the cutting-edge technological achievements, fundamental aspects are also discussed to cater to the inherently diverse background of the target audience, which results from the interdisciplinary nature of synthetic biology. The engineering of proteins as functional modules and the use of lipids and block copolymers as scaffold modules for the assembly of functionalized vesicular systems are explored in detail. Particular emphasis is placed on ensuring the controlled assembly of these components into increasingly complex vesicular systems. Finally, all descriptions are presented in the greater context of engineering valuable synthetic biological systems for applications in biocatalysis, biosensing, bioremediation, or targeted drug delivery.
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Affiliation(s)
- Stephan Hirschi
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland.,Molecular Systems Engineering, National Centre of Competence in Research (NCCR), 4002 Basel, Switzerland
| | - Thomas R Ward
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland.,Molecular Systems Engineering, National Centre of Competence in Research (NCCR), 4002 Basel, Switzerland
| | - Wolfgang P Meier
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland.,Molecular Systems Engineering, National Centre of Competence in Research (NCCR), 4002 Basel, Switzerland
| | - Daniel J Müller
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, 4058 Basel, Switzerland.,Molecular Systems Engineering, National Centre of Competence in Research (NCCR), 4002 Basel, Switzerland
| | - Dimitrios Fotiadis
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland.,Molecular Systems Engineering, National Centre of Competence in Research (NCCR), 4002 Basel, Switzerland
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20
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Cesana PT, Page CG, Harris D, Emmanuel MA, Hyster TK, Schlau-Cohen GS. Photoenzymatic Catalysis in a New Light: Gluconobacter “Ene”-Reductase Conjugates Possessing High-Energy Reactivity with Tunable Low-Energy Excitation. J Am Chem Soc 2022; 144:17516-17521. [DOI: 10.1021/jacs.2c06344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Paul T. Cesana
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Claire G. Page
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Dvir Harris
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Megan A. Emmanuel
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Todd K. Hyster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Gabriela S. Schlau-Cohen
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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21
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Pavlovska T, Král Lesný D, Svobodová E, Hoskovcová I, Archipowa N, Kutta RJ, Cibulka R. Tuning Deazaflavins Towards Highly Potent Reducing Photocatalysts Guided by Mechanistic Understanding – Enhancement of the Key Step by the Internal Heavy Atom Effect. Chemistry 2022; 28:e202200768. [PMID: 35538649 PMCID: PMC9541856 DOI: 10.1002/chem.202200768] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Indexed: 11/11/2022]
Abstract
Deazaflavins are well suited for reductive chemistry acting via a consecutive photo‐induced electron transfer, in which their triplet state and semiquinone – the latter is formed from the former after electron transfer from a sacrificial electron donor – are key intermediates. Guided by mechanistic investigations aiming to increase intersystem crossing by the internal heavy atom effect and optimising the concentration conditions to avoid unproductive excited singlet reactions, we synthesised 5‐aryldeazaflavins with Br or Cl substituents on different structural positions via a three‐component reaction. Bromination of the deazaisoalloxazine core leads to almost 100 % triplet yield but causes photo‐instability and enhances unproductive side reactions. Bromine on the 5‐phenyl group in ortho position does not affect the photostability, increases the triplet yield, and allows its efficient usage in the photocatalytic dehalogenation of bromo‐ and chloroarenes with electron‐donating methoxy and alkyl groups even under aerobic conditions. Reductive powers comparable to lithium are achieved.
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Affiliation(s)
- Tetiana Pavlovska
- Department of Organic Chemistry University of Chemistry and Technology, Prague Technická 5 166 28 Prague 6 Czech Republic
| | - David Král Lesný
- Department of Organic Chemistry University of Chemistry and Technology, Prague Technická 5 166 28 Prague 6 Czech Republic
| | - Eva Svobodová
- Department of Organic Chemistry University of Chemistry and Technology, Prague Technická 5 166 28 Prague 6 Czech Republic
| | - Irena Hoskovcová
- Department of Inorganic Chemistry University of Chemistry and Technology, Prague Technická 5 166 28 Prague 6 Czech Republic
| | - Nataliya Archipowa
- Institute for Biophysics and Physical Biochemistry University of Regensburg D-93053 Regensburg Germany
| | - Roger Jan Kutta
- Institute of Physical and Theoretical Chemistry University of Regensburg D-93053 Regensburg Germany
| | - Radek Cibulka
- Department of Organic Chemistry University of Chemistry and Technology, Prague Technická 5 166 28 Prague 6 Czech Republic
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22
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Laguerre N, Riehl PS, Oblinsky DG, Emmanuel MA, Black MJ, Scholes GD, Hyster TK. Radical Termination via β-Scission Enables Photoenzymatic Allylic Alkylation Using "Ene"-Reductases. ACS Catal 2022; 12:9801-9805. [PMID: 37859751 PMCID: PMC10586707 DOI: 10.1021/acscatal.2c02294] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Allylations are practical transformations that forge C-C bonds while introducing an alkene for further chemical manipulations. Here, we report a photoenzymatic allylation of α-chloroamides with allyl silanes using flavin-dependent 'ene'-reductases (EREDs). An engineered ERED can catalyze annulative allylic alkylation to prepare 5, 6, and 7-membered lactams with high levels of enantioselectivity. Ultrafast transient absorption spectroscopy indicates that radical termination occurs via β-scission of the silyl group to afford a silyl radical, a distinct mechanism by comparison to traditional radical allylations involving allyl silanes. Moreover, this represents an alternative strategy for radical termination using EREDs. This mechanism was applied to intermolecular couplings involving allyl sulfones and silyl enol ethers. Overall, this method highlights the opportunity for EREDs to catalyze radical termination strategies beyond hydrogen atom transfer.
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Affiliation(s)
| | | | - Daniel G. Oblinsky
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Megan A. Emmanuel
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Michael J. Black
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Gregory D. Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
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23
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Fu Y, Chen H, Fu W, Garcia-Borràs M, Yang Y, Liu P. Engineered P450 Atom-Transfer Radical Cyclases are Bifunctional Biocatalysts: Reaction Mechanism and Origin of Enantioselectivity. J Am Chem Soc 2022; 144:13344-13355. [PMID: 35830682 PMCID: PMC9339536 DOI: 10.1021/jacs.2c04937] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
New-to-nature radical biocatalysis has recently emerged as a powerful strategy to tame fleeting open-shell intermediates for stereoselective transformations. In 2021, we introduced a novel metalloredox biocatalysis strategy that leverages the innate redox properties of the heme cofactor of P450 enzymes, furnishing new-to-nature atom-transfer radical cyclases (ATRCases) with excellent activity and stereoselectivity. Herein, we report a combined computational and experimental study to shed light on the mechanism and origins of enantioselectivity for this system. Molecular dynamics and quantum mechanics/molecular mechanics (QM/MM) calculations revealed an unexpected role of the key beneficial mutation I263Q. The glutamine residue serves as an essential hydrogen bond donor that engages with the carbonyl moiety of the substrate to promote bromine atom abstraction and enhance the enantioselectivity of radical cyclization. Therefore, the evolved ATRCase is a bifunctional biocatalyst, wherein the heme cofactor enables atom-transfer radical biocatalysis, while the hydrogen bond donor residue further enhances the activity and enantioselectivity. Unlike many enzymatic stereocontrol rationales based on a rigid substrate binding model, our computations demonstrate a high degree of rotational flexibility of the allyl moiety in an enzyme-substrate complex and succeeding intermediates. Therefore, the enantioselectivity is controlled by the radical cyclization transition states rather than the substrate orientation in ground-state complexes in the preceding steps. During radical cyclization, anchoring effects of the Q263 residue and steric interactions with the heme cofactor concurrently control the π-facial selectivity, allowing for highly enantioselective C-C bond formation. Our computational findings are corroborated by experiments with ATRCase mutants generated from site-directed mutagenesis.
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Affiliation(s)
- Yue Fu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Heyu Chen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Wenzhen Fu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catalisi (IQCC) and Departament de Química, Universitat de Girona, Girona 17003, Spain
| | - Yang Yang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States.,Biomolecular Science and Engineering (BMSE) Program, University of California, Santa Barbara, California 93106, United States
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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24
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Zhuang B, Liebl U, Vos MH. Flavoprotein Photochemistry: Fundamental Processes and Photocatalytic Perspectives. J Phys Chem B 2022; 126:3199-3207. [PMID: 35442696 DOI: 10.1021/acs.jpcb.2c00969] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Flavins are highly versatile redox-active and colored cofactors in a large variety of proteins. These do include photoenzymes and photoreceptors, although the vast majority performs non-light-driven physiological functions. Nevertheless, electron transfer between flavins and specific nearby amino acid residues (in particular tyrosine, tryptophan, and presumably histidine and arginine) takes place upon excitation of flavin in many flavoproteins. For oxidized flavoproteins these reactions potentially have a photoprotective role. In this Perspective, we outline work on the characterization of early reaction intermediates not only in the relatively well-studied resting oxidized forms but also in the fully reduced and the intrinsically unstable semireduced forms, where ultrafast photooxidation of flavin was recently demonstrated. Along different lines, flavoprotein-based novel photocatalysts for biotechnological applications are presently emerging, employing both substrate photooxidation and photoreduction strategies. Deep insight into the fundamental flavin photochemical reactions may help in guiding and optimizing their development and in the exploration of novel photocatalytic approaches.
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Affiliation(s)
- Bo Zhuang
- LOB, CNRS, INSERM, Ecole Polytechnique, Institut Polytechnique de Paris, 91128 Palaiseau Cedex, France
| | - Ursula Liebl
- LOB, CNRS, INSERM, Ecole Polytechnique, Institut Polytechnique de Paris, 91128 Palaiseau Cedex, France
| | - Marten H Vos
- LOB, CNRS, INSERM, Ecole Polytechnique, Institut Polytechnique de Paris, 91128 Palaiseau Cedex, France
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25
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Abstract
Harnessing biocatalysts for novel abiological transformations is a longstanding goal of synthetic chemistry. Combining the merits of biocatalysis and photocatalysis allows for selective transformations fueled by visible light and offers many advantages including new reactivity, high enantioselectivity, greener syntheses, and high yields. Photoinduced electron or energy transfer enables synthetic methodologies that complement conventional two electron processes or offer orthogonal pathways for developing new reactions. Enzymes are well suited and can be tuned by directed evolution to exert control over open-shell intermediates, thereby suppressing undesirable reactions and delivering high chemo- and stereoselectivities. Within the past decade, the combination of biocatalysis and photocatalysis was mainly focused on exploiting light-regenerated cofactors to function native enzymatic activity. However, recent developments have demonstrated that the combination can unlock new-to-nature chemistry. Particularly, the discovery and application of new strategies are well poised to expand the applications of photobiocatalysis.In the past five years, our lab has been studying the combinations of photocatalysis and biocatalysis that can be applied to create new synthetic methodologies and solve challenges in synthetic organic chemistry. Our efforts have expanded the strategies for combining external photocatalysts with enzymes through the construction of a synergistic cooperative stereoconvergent reduction system consisting of photosensitized energy transfer and ene-reductase-catalyzed alkene reduction. Additionally, our efforts have also extended the capability of cofactor-dependent photoenzymatic systems to include enantioselective bimolecular radical hydroalkylations of alkenes by irradiating electron donor-acceptor complexes comprised of enzymatic redox active cofactors and unnatural substrates.In this Account, we highlight strategies developed by our group and others for combining biocatalysis and photocatalysis with the aim of introducing non-natural reactivity to enzymes. Presently, strategies applied to achieve this goal include the repurposing of natural photoenzymes, the elucidation of new photoreactivity within cofactor-dependent enzymes, the combination of external photocatalysts with enzymes, and the construction of artificial photoenzymes. By demonstrating the successful applications of these strategies for achieving selective new-to-nature transformations, we hope to spur interest in expanding the scope of photobiocatalytic systems through the use and extension of these strategies and creation of new strategies. Additionally, we hope to elucidate the intuition in synergizing the unique capabilities of biocatalysis and photocatalysis so that photobiocatalysis can be recognized as a potential solution to difficult challenges in synthetic organic chemistry.
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Affiliation(s)
- Wesley Harrison
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, 600 S. Matthews Avenue, Urbana, Illinois 61801, United States
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana−Champaign, 1206 W. Gregory Drive, Urbana, Illinois 61801, United States
| | - Xiaoqiang Huang
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, 600 S. Matthews Avenue, Urbana, Illinois 61801, United States
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana−Champaign, 1206 W. Gregory Drive, Urbana, Illinois 61801, United States
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, 600 S. Matthews Avenue, Urbana, Illinois 61801, United States
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana−Champaign, 1206 W. Gregory Drive, Urbana, Illinois 61801, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, 1206 W. Gregory Drive, Urbana, Illinois 61801, United States
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26
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Abstract
AbstractReductive radical cyclizations are ubiquitous in organic synthesis and have been applied to the synthesis of structurally complex molecules. N-Heterocyclic motifs can be prepared through the cyclization of α-haloamides; however, slow rotation around the amide C–N bond results in preferential formation of an acyclic hydrodehalogenated product. Here, we compare four different methods for preparing γ-, δ-, ε-, and ζ-lactams via radical cyclization. We found that a photoenzymatic method using flavin-dependent ‘ene’ reductases affords the highest level of product selectivity. We suggest that through selective binding of the cis-amide isomer, the enzyme preorganizes the substrate for cyclization, helping to avoid premature radical termination.
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27
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Gao X, Turek-Herman JR, Choi YJ, Cohen RD, Hyster TK. Photoenzymatic Synthesis of α-Tertiary Amines by Engineered Flavin-Dependent "Ene"-Reductases. J Am Chem Soc 2021; 143:19643-19647. [PMID: 34784482 PMCID: PMC10157440 DOI: 10.1021/jacs.1c09828] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
α-Tertiary amines are a common motif in pharmaceutically important molecules but are challenging to prepare using asymmetric catalysis. Here, we demonstrate engineered flavin-dependent 'ene'-reductases (EREDs) can catalyze radical additions into oximes to prepare this motif. Two different EREDs were evolved into competent catalysts for this transformation with high levels of stereoselectivity. Mechanistic studies indicate that the oxime contributes to the enzyme templated charge-transfer complex formed between the substrate and cofactor. These products can be further derivatized to prepare a variety of motifs, highlighting the versatility of ERED photoenzymatic catalysis for organic synthesis.
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Affiliation(s)
- Xin Gao
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Joshua R Turek-Herman
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.,Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Young Joo Choi
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Ryan D Cohen
- Analytical Research & Development, Merck & Company Inc., Rahway, New Jersey 07065, United States
| | - Todd K Hyster
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.,Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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