1
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Xu W, Fan C, Hu X, Xu T. Deoxygenative Transformation of Alcohols via Phosphoranyl Radical from Exogenous Radical Addition. Angew Chem Int Ed Engl 2024; 63:e202401575. [PMID: 38357753 DOI: 10.1002/anie.202401575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 02/13/2024] [Accepted: 02/15/2024] [Indexed: 02/16/2024]
Abstract
A general approach to the direct deoxygenative transformation of primary, secondary, and tertiary alcohols has been developed. It undergoes through phosphoranyl radical intermediates generated by the addition of exogenous iodine radical to trivalent alkoxylphosphanes. Since these alkoxylphosphanes are readily in situ obtained from alcohols and commercially available, inexpensive chlorodiphenylphosphine, a diverse range of alcohols with various functional groups can be utilized to proceed deoxygenative cross-couplings with alkenes or aryl iodides. The selective transformation of polyhydroxy substrates and the rapid synthesis of complex organic molecules are also demonstrated with this method.
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Affiliation(s)
- Wenhao Xu
- Shanghai Key Laboratory of Chemical Assessment and Sustain-ability, School of Chemical Science and Engineering, Tongji University, 1239 Siping Road, 200092, Shanghai, P. R. China
| | - Chao Fan
- Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Xile Hu
- Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Tao Xu
- Shanghai Key Laboratory of Chemical Assessment and Sustain-ability, School of Chemical Science and Engineering, Tongji University, 1239 Siping Road, 200092, Shanghai, P. R. China
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2
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Gould CA, Pace AL, MacMillan DWC. Rapid and Modular Access to Quaternary Carbons from Tertiary Alcohols via Bimolecular Homolytic Substitution. J Am Chem Soc 2023; 145:16330-16336. [PMID: 37471294 PMCID: PMC10680126 DOI: 10.1021/jacs.3c05405] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
Quaternary carbons are ubiquitous in bioactive molecules; however, synthetic methods for the construction of this motif remain underdeveloped. Here, we report the synthesis of quaternary carbons from tertiary alcohols, a class of structurally diverse, bench-stable feedstocks, via the merger of photoredox catalysis and iron-mediated SH2 bond formation. This alcohol-bromide cross-coupling is enabled by a novel halogen-atom transfer (XAT) reagent, which is the first reductively activated XAT reagent to be reported. A wide variety of sterically congested quaternary products can be accessed through this mild and practical protocol including products derived from both alkylation and benzylation of tertiary fragments. We further demonstrate the synthetic utility of this method through the expedited synthesis of a liver receptor agonist and through a two-step conversion of ketones and esters to quaternary products, which enables the modular control of up to three of the four substituents on a quaternary center.
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Affiliation(s)
- Colin A Gould
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States
| | - Andria L Pace
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States
| | - David W C MacMillan
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States
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3
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Wang JZ, Sakai HA, MacMillan DWC. Alcohols as Alkylating Agents: Photoredox-Catalyzed Conjugate Alkylation via In Situ Deoxygenation. Angew Chem Int Ed Engl 2022; 61:e202207150. [PMID: 35727296 PMCID: PMC9398968 DOI: 10.1002/anie.202207150] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Indexed: 11/10/2022]
Abstract
The rapid exploration of sp3 -enriched chemical space is facilitated by fragment-coupling technologies that utilize simple and abundant alkyl precursors, among which alcohols are a highly desirable, commercially accessible, and synthetically versatile class of substrate. Herein, we describe an operationally convenient, N-heterocyclic carbene (NHC)-mediated deoxygenative Giese-type addition of alcohol-derived alkyl radicals to electron-deficient alkenes under mild photocatalytic conditions. The fragment coupling accommodates a broad range of primary, secondary, and tertiary alcohol partners, as well as structurally varied Michael acceptors containing traditionally reactive sites, such as electrophilic or oxidizable moieties. We demonstrate the late-stage diversification of densely functionalized molecular architectures, including drugs and biomolecules, and we further telescope our protocol with metallaphotoredox cross-coupling for step-economic access to sp3 -rich complexity.
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Affiliation(s)
- Johnny Z Wang
- Merck Center for Catalysis at Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Holt A Sakai
- Merck Center for Catalysis at Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - David W C MacMillan
- Merck Center for Catalysis at Princeton University, Washington Road, Princeton, NJ 08544, USA
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4
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Romano C, Talavera L, Gómez-Bengoa E, Martin R. Conformational Flexibility as a Tool for Enabling Site-Selective Functionalization of Unactivated sp3 C-O Bonds in Cyclic Acetals. J Am Chem Soc 2022; 144:11558-11563. [PMID: 35749319 PMCID: PMC9264358 DOI: 10.1021/jacs.2c04513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
A dual catalytic
manifold that enables site-selective functionalization
of unactivated sp3 C–O
bonds in cyclic acetals with aryl and alkyl halides is reported. The
reaction is triggered by an appropriate σ*–p orbital
overlap prior to sp3 C–O
cleavage, thus highlighting the importance of conformational flexibility
in both reactivity and site selectivity. The protocol is characterized
by its excellent chemoselectivity profile, thus offering new vistas
for activating strong σ sp3 C–O linkages.
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Affiliation(s)
- Ciro Romano
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain
| | - Laura Talavera
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain.,Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, c/Marcel·lí Domingo, 1, 43007 Tarragona, Spain
| | - Enrique Gómez-Bengoa
- Department of Organic Chemistry I, Universidad País Vasco, UPV/EHU, Apdo. 1072, 20080, San Sebastian, Spain
| | - Ruben Martin
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain.,ICREA, Passeig Lluís Companys, 23, 08010 Barcelona, Spain
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5
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Wang JZ, Sakai HA, MacMillan DWC. Alcohols as Alkylating Agents: Photoredox‐Catalyzed Conjugate Alkylation via In Situ Deoxygenation. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202207150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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6
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Sakai HA, MacMillan DWC. Nontraditional Fragment Couplings of Alcohols and Carboxylic Acids: C( sp3)-C( sp3) Cross-Coupling via Radical Sorting. J Am Chem Soc 2022; 144:6185-6192. [PMID: 35353531 DOI: 10.1021/jacs.2c02062] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Alcohols and carboxylic acids are among the most commercially abundant, synthetically versatile, and operationally convenient functional groups in organic chemistry. Under visible light photoredox catalysis, these native synthetic handles readily undergo radical activation, and the resulting open-shell intermediates can subsequently participate in transition metal catalysis. In this report, we describe the C(sp3)-C(sp3) cross-coupling of alcohols and carboxylic acids through the dual combination of N-heterocyclic carbene (NHC)-mediated deoxygenation and hypervalent iodine-mediated decarboxylation. This mild and practical Ni-catalyzed radical-coupling protocol was employed to prepare a wide array of alkyl-alkyl cross-coupled products, including highly congested quaternary carbon centers from the corresponding tertiary alcohols or tertiary carboxylic acids. We demonstrate the synthetic applications of this methodology to alcohol C1-alkylation and formal homologation, as well as to the late-stage functionalization of drugs, natural products, and biomolecules.
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Affiliation(s)
- Holt A Sakai
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States
| | - David W C MacMillan
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States
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7
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Wang JX, Ge W, Fu MC, Fu Y. Photoredox-Catalyzed Allylic Defluorinative Alkoxycarbonylation of Trifluoromethyl Alkenes through Intermolecular Alkoxycarbonyl Radical Addition. Org Lett 2022; 24:1471-1475. [PMID: 35167309 DOI: 10.1021/acs.orglett.1c04359] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The gem-difluoroalkene moiety is an ideal carbonyl bioisostere in medicinal chemistry, but efficient synthesis of β-gem-difluoroalkene esters remains challenging so far. Herein, we disclose a photoredox-catalyzed allylic defluorinative alkoxycarbonylation of trifluoromethyl alkenes enabled by intermolecular alkoxycarbonyl radical addition. A wide variety of alcohol oxalate derivatives were amenable, affording various β-gem-difluoroalkene esters with excellent functional group tolerance. Notably, the potential synthetic value of this method is highlighted by successful late-stage modification for bioactive molecules.
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Affiliation(s)
- Jia-Xin Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, iChEM, University of Science and Technology of China, Hefei 230026, China
| | - Wei Ge
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, iChEM, University of Science and Technology of China, Hefei 230026, China
| | - Ming-Chen Fu
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, iChEM, University of Science and Technology of China, Hefei 230026, China
| | - Yao Fu
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, iChEM, University of Science and Technology of China, Hefei 230026, China
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8
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Liu Q, Han F, Zhuang H, Zhang T, Ji N, Miao C. Direct deoxygenation of active allylic alcohols via metal-free catalysis. Org Biomol Chem 2022; 20:1680-1689. [DOI: 10.1039/d1ob02168k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Direct metal-free deoxygenation of highly active allylic alcohols catalyzed by a Brønsted acid was achieved, which avoids tedious reaction steps and eliminates metal contamination. By examining a series of Brønsted...
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9
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Chinn AJ, Sedillo K, Doyle AG. Phosphine/Photoredox Catalyzed Anti-Markovnikov Hydroamination of Olefins with Primary Sulfonamides via α-Scission from Phosphoranyl Radicals. J Am Chem Soc 2021; 143:18331-18338. [PMID: 34672192 DOI: 10.1021/jacs.1c09484] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
New strategies to access radicals from common feedstock chemicals hold the potential to broadly impact synthetic chemistry. We report a dual phosphine and photoredox catalytic system that enables direct formation of sulfonamidyl radicals from primary sulfonamides. Mechanistic investigations support that the N-centered radical is generated via α-scission of the P-N bond of a phosphoranyl radical intermediate, formed by sulfonamide nucleophilic addition to a phosphine radical cation. As compared to the recently well-explored β-scission chemistry of phosphoranyl radicals, this strategy is applicable to activation of N-based nucleophiles and is catalytic in phosphine. We highlight application of this activation strategy to an intermolecular anti-Markovnikov hydroamination of unactivated olefins with primary sulfonamides. A range of structurally diverse secondary sulfonamides can be prepared in good to excellent yields under mild conditions.
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Affiliation(s)
- Alex J Chinn
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Kassandra Sedillo
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Abigail G Doyle
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.,Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
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10
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Abstract
Metal-catalysed cross-couplings are a mainstay of organic synthesis and are widely used for the formation of C-C bonds, particularly in the production of unsaturated scaffolds1. However, alkyl cross-couplings using native sp3-hybridized functional groups such as alcohols remain relatively underdeveloped2. In particular, a robust and general method for the direct deoxygenative coupling of alcohols would have major implications for the field of organic synthesis. A general method for the direct deoxygenative cross-coupling of free alcohols must overcome several challenges, most notably the in situ cleavage of strong C-O bonds3, but would allow access to the vast collection of commercially available, structurally diverse alcohols as coupling partners4. We report herein a metallaphotoredox-based cross-coupling platform in which free alcohols are activated in situ by N-heterocyclic carbene salts for carbon-carbon bond formation with aryl halide coupling partners. This method is mild, robust, selective and most importantly, capable of accommodating a wide range of primary, secondary and tertiary alcohols as well as pharmaceutically relevant aryl and heteroaryl bromides and chlorides. The power of the transformation has been demonstrated in a number of complex settings, including the late-stage functionalization of Taxol and a modular synthesis of Januvia, an antidiabetic medication. This technology represents a general strategy for the merger of in situ alcohol activation with transition metal catalysis.
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Affiliation(s)
- Zhe Dong
- Merck Center for Catalysis at Princeton University, Princeton, NJ, USA
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11
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Liu Y, Shi Y, Wei L, Zhao K, Zhao J, Zhang P, Xu X, Li P. Gold-Catalyzed One-Pot Synthesis of Polyfluoroalkylated Oxazoles from N-Propargylamides Under Visible-Light Irradiation. Chem Asian J 2021; 16:2417-2420. [PMID: 34235859 DOI: 10.1002/asia.202100614] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/29/2021] [Indexed: 11/11/2022]
Abstract
A gold-catalyzed synthesis of polyfluoroalkylated oxazoles from N-propargylamides under visible-light irradiation has been developed. These reactions display excellent compatibility of radicals and gold catalysts under visible-light irradiation. Mechanistic experiments indicate that polyfluoroalkyl iodides play a dual role in enhanced compatibility of radicals and gold catalysts through assisted protodeauration of vinyl gold and reactivated the gold catalyst. In addition, PPh3 AuNTf2 not only activates N-propargylamide to generate vinyl gold intermediate, but also greatly promotes homolysis of polyfluoroalkyl iodides under blue light irradiation.
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Affiliation(s)
- Yantao Liu
- Department Institute of Functional Organic Molecular Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, P. R. China
| | - Yating Shi
- Department Institute of Functional Organic Molecular Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, P. R. China
| | - Lanen Wei
- Department Institute of Functional Organic Molecular Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, P. R. China
| | - Ke Zhao
- Department Institute of Functional Organic Molecular Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, P. R. China
| | - Jingjing Zhao
- Department Institute of Functional Organic Molecular Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, P. R. China
| | - Puyu Zhang
- Department Institute of Functional Organic Molecular Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, P. R. China
| | - Xuejun Xu
- Department Institute of Functional Organic Molecular Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, P. R. China
| | - Pan Li
- Department Institute of Functional Organic Molecular Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, P. R. China
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12
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Abstract
Given their ubiquity in natural products and pharmaceuticals, alcohols represent one of the most attractive starting materials for the construction of C-C bonds. We report herein the first catalytic strategy to harness the reactivity of aryl radicals for the activation of C-O bonds in alcohol-derived xanthate esters, allowing for the discovery of the first catalytic deoxygenative difluoromethylation reaction. Under copper-catalyzed conditions, a wide variety of alkyl xanthate esters, readily synthesized from alcohol feedstocks, were activated by catalytically generated aryl radicals and were converted to the alkyl-difluoromethane products via alkyl radical intermediates. This scalable protocol exhibits a broad substrate scope and functional group tolerance, enabling late-stage modification of complex pharmaceutical agents. A one-pot protocol has been developed that allows for the direct use of free alcohols without purification of the xanthate esters. Mechanistic studies are consistent with the hypothesis of aryl radicals being formed and initiating the cleavage of the C-O bonds of xanthate esters, to generate alkyl radicals as the key intermediates. This aryl radical activation approach represents a new strategy for the activation of alcohols as cross-coupling partners.
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Affiliation(s)
- Aijie Cai
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Wenhao Yan
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Wei Liu
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
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13
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Wei Y, Ben-Zvi B, Diao T. Diastereoselective Synthesis of Aryl C-Glycosides from Glycosyl Esters via C-O Bond Homolysis. Angew Chem Int Ed Engl 2021; 60:9433-9438. [PMID: 33438338 PMCID: PMC8044010 DOI: 10.1002/anie.202014991] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/10/2020] [Indexed: 12/20/2022]
Abstract
C-aryl glycosyl compounds offer better in vivo stability relative to O- and N-glycoside analogues. C-aryl glycosides are extensively investigated as drug candidates and applied to chemical biology studies. Previously, C-aryl glycosides were derived from lactones, glycals, glycosyl stannanes, and halides, via methods displaying various limitations with respect to the scope, functional-group compatibility, and practicality. Challenges remain in the synthesis of C-aryl nucleosides and 2-deoxysugars from easily accessible carbohydrate precursors. Herein, we report a cross-coupling method to prepare C-aryl and heteroaryl glycosides, including nucleosides and 2-deoxysugars, from glycosyl esters and bromoarenes. Activation of the carbohydrate substrates leverages dihydropyridine (DHP) as an activating group followed by decarboxylation to generate a glycosyl radical via C-O bond homolysis. This strategy represents a new means to activate alcohols as a cross-coupling partner. The convenient preparation of glycosyl esters and their stability exemplifies the potential of this method in medicinal chemistry.
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Affiliation(s)
- Yongliang Wei
- Chemistry Department, New York University, 100 Washington Square East, New York, NY, 10003, USA
| | - Benjamin Ben-Zvi
- Chemistry Department, New York University, 100 Washington Square East, New York, NY, 10003, USA
| | - Tianning Diao
- Chemistry Department, New York University, 100 Washington Square East, New York, NY, 10003, USA
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14
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Affiliation(s)
- Yongliang Wei
- Chemistry Department New York University 100 Washington Square East New York NY 10003 USA
| | - Benjamin Ben‐zvi
- Chemistry Department New York University 100 Washington Square East New York NY 10003 USA
| | - Tianning Diao
- Chemistry Department New York University 100 Washington Square East New York NY 10003 USA
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15
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Affiliation(s)
- Sina Witzel
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - A. Stephen K. Hashmi
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
- Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Jin Xie
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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16
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Cao D, Chen Z, Lv L, Zeng H, Peng Y, Li CJ. Light-Driven Metal-Free Direct Deoxygenation of Alcohols under Mild Conditions. iScience 2020; 23:101419. [PMID: 32798970 PMCID: PMC7452908 DOI: 10.1016/j.isci.2020.101419] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/02/2020] [Accepted: 07/24/2020] [Indexed: 12/18/2022] Open
Abstract
Hydroxyl is widely found in organic molecules as functional group and its deprivation plays an inevitable role in organic synthesis. However, the direct cleavage of Csp3-O bond in alcohols with high selectivity and efficiency, especially without the assistance of metal catalyst, has been a formidable challenge because of its strong bond dissociation energy and unfavorable thermodynamics. Herein, an efficient metal-free strategy that enables direct deoxygenation of alcohols has been developed for the first time, with hydrazine as the reductant induced by light. This protocol features mild reaction conditions, excellent functional group tolerance, and abundant and easily available starting materials, rendering selective deoxygenation of a variety of 1° and 2° alcohols, vicinal diols, and β-1 and even β-O-4 models of natural wood lignin. This strategy is also highlighted by its “traceless” and non-toxic by-products N2 and H2, as readily escapable gases. Mechanistic studies demonstrated dimethyl sulfide being a key intermediate in this transformation. Metal-free direct deoxygenation of alcohols enabled by light Traceless non-toxic N2 and H2 as by-products Broad substrate scope and wide functional group compatibility Converting lignin models into simple aromatics
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Affiliation(s)
- Dawei Cao
- Department of Chemistry and FRQNT Centre for Green Chemistry and Catalysis, McGill University, 801 Sherbrooke St. West, Montreal, QC H3A 0B8, Canada; Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology and Electron Microscopy Centre, Lanzhou University, Lanzhou 730000, P. R. China; The State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, P. R. China
| | - Zhangpei Chen
- Department of Chemistry and FRQNT Centre for Green Chemistry and Catalysis, McGill University, 801 Sherbrooke St. West, Montreal, QC H3A 0B8, Canada
| | - Leiyang Lv
- Department of Chemistry and FRQNT Centre for Green Chemistry and Catalysis, McGill University, 801 Sherbrooke St. West, Montreal, QC H3A 0B8, Canada
| | - Huiying Zeng
- The State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, P. R. China
| | - Yong Peng
- Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology and Electron Microscopy Centre, Lanzhou University, Lanzhou 730000, P. R. China
| | - Chao-Jun Li
- Department of Chemistry and FRQNT Centre for Green Chemistry and Catalysis, McGill University, 801 Sherbrooke St. West, Montreal, QC H3A 0B8, Canada.
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17
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Rossi-Ashton JA, Clarke AK, Unsworth WP, Taylor RJK. Phosphoranyl Radical Fragmentation Reactions Driven by Photoredox Catalysis. ACS Catal 2020; 10:7250-7261. [PMID: 32905246 PMCID: PMC7469205 DOI: 10.1021/acscatal.0c01923] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/04/2020] [Indexed: 12/17/2022]
Abstract
Photocatalytic generation of phosphoranyl radicals is fast emerging as an essential method for the generation of diverse and valuable radicals, typically via deoxygenation or desulfurization processes. This Perspective is a comprehensive evaluation of all studies using phosphoranyl radicals as tunable mediators in photoredox catalysis, highlighting how two distinct methods for phosphoranyl radical formation (radical addition and nucleophilic addition) can be used to generate versatile radical intermediates with diverse reactivity profiles.
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Affiliation(s)
| | - Aimee K. Clarke
- Department of Chemistry, University of York, Heslington,
York YO10 5DD, U.K.
| | - William P. Unsworth
- Department of Chemistry, University of York, Heslington,
York YO10 5DD, U.K.
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18
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Abstract
Although carbon radicals generated from a variety of alcohol derivatives have proven valuable in coupling and addition reactions, the direct use of alcohols as synthetically useful radical sources is less known. In this report, benzylic alcohols are shown to be effective radical precursors for addition reactions to alkenes when treated with triphenylphosphine or piperidine with the catalyst ReIO2(PPh3)2 (I).
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Affiliation(s)
- Chandrasekhar Bandari
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Kenneth M Nicholas
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
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19
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Abstract
The background and recent breakthroughs in the single-electron-transfer (SET) reactions with trivalent tertiary phosphines are summarized and discussed in detail, and an outlook in the developments within this field is provided.
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Affiliation(s)
- Dingwu Pan
- Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering
- Key Laboratory of Green Pesticide and Agricultural Bioengineering Ministry of Education
- Guizhou University
- Guiyang 550025
- China
| | - Guihua Nie
- Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering
- Key Laboratory of Green Pesticide and Agricultural Bioengineering Ministry of Education
- Guizhou University
- Guiyang 550025
- China
| | - Shichun Jiang
- Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering
- Key Laboratory of Green Pesticide and Agricultural Bioengineering Ministry of Education
- Guizhou University
- Guiyang 550025
- China
| | - Tingting Li
- Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering
- Key Laboratory of Green Pesticide and Agricultural Bioengineering Ministry of Education
- Guizhou University
- Guiyang 550025
- China
| | - Zhichao Jin
- Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering
- Key Laboratory of Green Pesticide and Agricultural Bioengineering Ministry of Education
- Guizhou University
- Guiyang 550025
- China
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20
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Abstract
Alcohols and carboxylic acids have been established as versatile building blocks in the assembly of various carbon frameworks.
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Affiliation(s)
- Xiao-Qiang Hu
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science
- School of Chemistry and Materials Science
- South-Central University for Nationalities
- Wuhan 430074
- China
| | - Ye-Xing Hou
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science
- School of Chemistry and Materials Science
- South-Central University for Nationalities
- Wuhan 430074
- China
| | - Zi-Kui Liu
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science
- School of Chemistry and Materials Science
- South-Central University for Nationalities
- Wuhan 430074
- China
| | - Yang Gao
- School of Chemical Engineering and Light Industry
- Guangdong University of Technology
- Guangzhou
- China
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21
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Garrido-Castro AF, Salaverri N, Maestro MC, Alemán J. Intramolecular Homolytic Substitution Enabled by Photoredox Catalysis: Sulfur, Phosphorus, and Silicon Heterocycle Synthesis from Aryl Halides. Org Lett 2019; 21:5295-5300. [DOI: 10.1021/acs.orglett.9b01911] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
| | - Noelia Salaverri
- Department of Organic Chemistry, Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - M. Carmen Maestro
- Department of Organic Chemistry, Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - José Alemán
- Department of Organic Chemistry, Universidad Autónoma de Madrid, Madrid 28049, Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, Madrid 28049, Spain
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22
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Yamana K, Nakano H. Synthesis of polycyclic phosphonates via an intramolecular Diels-Alder reaction of 2-benzoylbenzalaldehyde and alkenyl phosphites. HETEROCYCL COMMUN 2019. [DOI: 10.1515/hc-2019-0011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
AbstractIn this paper, we present a Lewis-acid-promoted reaction of 2-benzoylbenzaldehyde and trialkenyl phosphites, which resulted in the formation of polycyclic phosphonates. The reaction proceeded via nucleophilic attack of trialkenyl phosphite on the carbonyl carbon of 2-benzoylbenzaldehyde. The subsequent intramolecular Diels-Alder reaction led to the formation of the cyclic phosphonate.
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Affiliation(s)
- Kenji Yamana
- Division of Liberal Arts and Sciences, Aichi Gakuin University, Araike 12, Iwasaki, Nisshin, Aichi 470-0195, Japan
| | - Hirofumi Nakano
- Department of Chemistry, Aichi University of Education, Igaya, Kariya, Aichi 448-8542, Japan
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23
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Han JB, Guo A, Tang XY. Alkylation of Allyl/Alkenyl Sulfones by Deoxygenation of Alkoxyl Radicals. Chemistry 2019; 25:2989-2994. [PMID: 30624002 DOI: 10.1002/chem.201806138] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/04/2019] [Indexed: 11/12/2022]
Abstract
A challenging deoxygenation of alkoxyl radicals from readily accessible alcohol derivatives was developed, affording facile synthesis of functionalized alkenes with good functional group tolerance under mild reaction conditions. Because alkoxyl radicals can easily undergo β-fragmentations or hydrogen abstractions, this new strategy for deoxygenation of alkoxyl radicals is highly valuable. Moreover, mechanistic studies revealed that the electron-neutral phosphine acts as the deoxygenation reagent.
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Affiliation(s)
- Jia-Bin Han
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, 430074, P. R. China
| | - Ao Guo
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, 430074, P. R. China
| | - Xiang-Ying Tang
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, 430074, P. R. China
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24
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Stache EE, Ertel AB, Rovis T, Doyle AG. Generation of Phosphoranyl Radicals via Photoredox Catalysis Enables Voltage-Independent Activation of Strong C-O Bonds. ACS Catal 2018; 8:11134-11139. [PMID: 31367474 DOI: 10.1021/acscatal.8b03592] [Citation(s) in RCA: 166] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Despite the prevalence of alcohols and carboxylic acids as functional groups in organic molecules and the potential to serve as radical precursors, C-O bonds remain difficult to activate. We report a synthetic strategy for direct access to both alkyl and acyl radicals from these ubiquitous functional groups via photoredox catalysis. This method exploits the unique reactivity of phosphoranyl radicals, generated from a polar/SET crossover between a phosphine radical cation and an oxygen-centered nucleophile. We show the desired reactivity in the reduction of benzylic alcohols to the corresponding benzyl radicals with terminal H atom trapping to afford the deoxygenated products. Using the same method, we demonstrate access to synthetically versatile acyl radicals, which enables the reduction of aromatic and aliphatic carboxylic acids to the corresponding aldehydes with exceptional chemoselectivity. This protocol also transforms carboxylic acids to heterocycles and cyclic ketones via intramolecular acyl radical cyclizations to forge C-O, C-N, and C-C bonds in a single step.
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Affiliation(s)
- Erin E. Stache
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
- Department of Chemistry and Chemical Biology, Cornell University, Baker Lab, Ithaca, New York 14853, United States
| | - Alyssa B. Ertel
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Tomislav Rovis
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Abigail G. Doyle
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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25
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Wang Y, Shao Z, Zhang K, Liu Q. Manganese‐Catalyzed Dual‐Deoxygenative Coupling of Primary Alcohols with 2‐Arylethanols. Angew Chem Int Ed Engl 2018; 57:15143-15147. [DOI: 10.1002/anie.201809333] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Indexed: 12/23/2022]
Affiliation(s)
- Yujie Wang
- Center of Basic Molecular Science (CBMS)Department of ChemistryTsinghua University Beijing 100084 China
| | - Zhihui Shao
- Center of Basic Molecular Science (CBMS)Department of ChemistryTsinghua University Beijing 100084 China
| | - Kun Zhang
- School of Biotechnology and Health SciencesWuyi University Jiangmen Guangdong Province 529090 China
| | - Qiang Liu
- Center of Basic Molecular Science (CBMS)Department of ChemistryTsinghua University Beijing 100084 China
- School of Biotechnology and Health SciencesWuyi University Jiangmen Guangdong Province 529090 China
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26
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Affiliation(s)
- Yujie Wang
- Center of Basic Molecular Science (CBMS)Department of ChemistryTsinghua University Beijing 100084 China
| | - Zhihui Shao
- Center of Basic Molecular Science (CBMS)Department of ChemistryTsinghua University Beijing 100084 China
| | - Kun Zhang
- School of Biotechnology and Health SciencesWuyi University Jiangmen Guangdong Province 529090 China
| | - Qiang Liu
- Center of Basic Molecular Science (CBMS)Department of ChemistryTsinghua University Beijing 100084 China
- School of Biotechnology and Health SciencesWuyi University Jiangmen Guangdong Province 529090 China
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27
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Affiliation(s)
- Masahiro Sai
- Research Foundation ITSUU Laboratory; C1232 Kanagawa Science Park R & D Building, 3-2-1 Sakado, Takatsu-ku, Kawasaki; Kanagawa 213-0012 Japan
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28
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Affiliation(s)
- Samuel W. Lardy
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Valerie A. Schmidt
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
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29
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Affiliation(s)
- Takuya Suga
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
| | - Shoma Shimazu
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
| | - Yutaka Ukaji
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
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30
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Affiliation(s)
- Masahiro Sai
- Research Foundation ITSUU Laboratory; C1232 Kanagawa Science Park R & D Building, 3-2-1 Sakado, Takatsu-ku, Kawasaki Kanagawa 213-0012 Japan
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31
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Abstract
The application of small molecules as catalysts for the diversification of natural product scaffolds is reviewed. Specifically, principles that relate to the selectivity challenges intrinsic to complex molecular scaffolds are summarized. The synthesis of analogues of natural products by this approach is then described as a quintessential "late-stage functionalization" exercise wherein natural products serve as the lead scaffolds. Given the historical application of enzymatic catalysts to the site-selective alteration of complex molecules, the focus of this Review is on the recent studies of nonenzymatic catalysts. Reactions involving hydroxyl group derivatization with a variety of electrophilic reagents are discussed. C-H bond functionalizations that lead to oxidations, aminations, and halogenations are also presented. Several examples of site-selective olefin functionalizations and C-C bond formations are also included. Numerous classes of natural products have been subjected to these studies of site-selective alteration including polyketides, glycopeptides, terpenoids, macrolides, alkaloids, carbohydrates, and others. What emerges is a platform for chemical remodeling of naturally occurring scaffolds that targets virtually all known chemical functionalities and microenvironments. However, challenges for the design of very broad classes of catalysts, with even broader selectivity demands (e.g., stereoselectivity, functional group selectivity, and site-selectivity) persist. Yet, a significant spectrum of powerful, catalytic alterations of complex natural products now exists such that expansion of scope seems inevitable. Several instances of biological activity assays of remodeled natural product derivatives are also presented. These reports may foreshadow further interdisciplinary impacts for catalytic remodeling of natural products, including contributions to SAR development, mode of action studies, and eventually medicinal chemistry.
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Affiliation(s)
- Christopher R. Shugrue
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Scott J. Miller
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
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32
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Affiliation(s)
- Jonathan O. Bauer
- Department of Organic Chemistry, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Subrata Chakraborty
- Department of Organic Chemistry, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - David Milstein
- Department of Organic Chemistry, The Weizmann Institute of Science, 76100 Rehovot, Israel
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33
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Affiliation(s)
- Sarwat Chowdhury
- Department
of Chemistry, The University of Illinois at Chicago, 845 West
Taylor Street, Chicago, Illinois 60304, United States
| | - Robert F. Standaert
- Biosciences
Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, Tennessee 37831-6445, United States
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, United States
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34
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Yang Z, Kumar RK, Liao P, Liu Z, Li X, Bi X. Chemo- and regioselective reductive deoxygenation of 1-en-4-yn-ols into 1,4-enynes through FeF3 and TfOH co-catalysis. Chem Commun (Camb) 2016; 52:5936-9. [DOI: 10.1039/c5cc10518h] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We report chemo- and regioselective direct reductive deoxygenation of 1-en-4-yn-3-ols into 1,4-enynes through FeF3 and TfOH cooperative catalysis under NBSH-mediated conditions.
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Affiliation(s)
- Zonglian Yang
- Department of Chemistry
- Northeast Normal University
- 130024 Changchun
- China
| | | | - Peiqiu Liao
- Department of Chemistry
- Northeast Normal University
- 130024 Changchun
- China
| | - Zhaohong Liu
- Department of Chemistry
- Northeast Normal University
- 130024 Changchun
- China
| | - Xingqi Li
- Department of Chemistry
- Northeast Normal University
- 130024 Changchun
- China
| | - Xihe Bi
- Department of Chemistry
- Northeast Normal University
- 130024 Changchun
- China
- State Key Laboratory of Elemento-Organic Chemistry
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35
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El-Desoky ESI, Reyad M, Afsah EM, Dawidar AAM. Synthesis and chemical reactions of the steroidal hormone 17α-methyltestosterone. Steroids 2016; 105:68-95. [PMID: 26639430 DOI: 10.1016/j.steroids.2015.11.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 11/11/2015] [Accepted: 11/19/2015] [Indexed: 11/30/2022]
Abstract
Structural modifications of natural products with complex structures like steroids require great synthetic effort. A review of literature is presented on the chemistry of the steroidal hormone 17α-methyltestosterone that is approved by Food and Drug Administration (FDA) in the United States as an androgen for estrogen-androgen hormone replacement therapy treatment. The analog also offers special possibilities for the prevention/treatment of hormone-sensitive cancers. The testosterone skeleton has important functionalities in the molecule that can act as a carbonyl component, an active methylene compound, α,β-unsaturated enone and tertiary hydroxyl group in various chemical reactions to access stereoisomeric steroidal compounds with potent activity. In addition, microbiological methods of synthesis and transformation of this hormone are presented.
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Affiliation(s)
- El-Sayed Ibrahim El-Desoky
- Chemistry Department, Faculty of Science, Mansoura University, 60, El Gomhoria Street, Mansoura Dakahlia 35516, Egypt
| | - Mahmoud Reyad
- Chemistry Department, Faculty of Science, Mansoura University, 60, El Gomhoria Street, Mansoura Dakahlia 35516, Egypt.
| | - Elsayed Mohammed Afsah
- Chemistry Department, Faculty of Science, Mansoura University, 60, El Gomhoria Street, Mansoura Dakahlia 35516, Egypt
| | - Abdel-Aziz Mahmoud Dawidar
- Chemistry Department, Faculty of Science, Mansoura University, 60, El Gomhoria Street, Mansoura Dakahlia 35516, Egypt
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36
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Patel SN, Pandya K, Clark GJ, Parikh MC, Lau-Cam CA. Comparison of taurine and pantoyltaurine as antioxidants in vitro and in the central nervous system of diabetic rats. ACTA ACUST UNITED AC 2015; 68:103-12. [PMID: 26616540 DOI: 10.1016/j.etp.2015.11.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Revised: 09/29/2015] [Accepted: 11/09/2015] [Indexed: 01/08/2023]
Abstract
This study has comparatively evaluated the antiradical and antilipid peroxidizing actions of taurine (TAU) and its N-pantoyl analog pantoyltaurine (PTAU) in vitro, and has determined the extent to which these findings agree with the in vivo ability of these compounds to prevent changes in plasma glucose and in indices of oxidative stress in the plasma, brain and spinal cord induced by the diabetogen streptozotocin (STZ) in Sprague-Dawley rats. Using free radical-generating and oxidizing systems, PTAU was found more effective than TAU in scavenging DPPH, hydroxyl, peroxyl, and superoxide anion radicals and peroxynitrite, and in preventing lipid peroxidation of a brain homogenate by iron (III)-dopamine and the oxidation of dopamine by iron (III). On the other hand, when administered intraperitoneally (i.p.) at a 1.2mM/kg dose, 75min and 45min before a single i.p., 60mg/kg, dose of (STZ), TAU was about equipotent with PTAU in attenuating STZ-induced increases in glucose, malondialdehyde (MDA) and nitric oxide (NO), and the loss of reduced glutathione (GSH) in plasma collected at 24h post STZ. Moreover, the analysis of concurrently collected brain and spinal cords samples revealed that both TAU and PTAU were able to equally reverse the increases in MDA and NO concentrations and to effectively counteract the decrease in the GSH/GSSG ratio caused by STZ. Likewise, both compounds were very effective in preventing the losses of tissue catalase, glutathione peroxidase and superoxide dismutase activities. A comparison of the results for spinal cord and for brain parts such as the cerebellum, cortex and brain stem suggested the existence of regional differences in antioxidant potency between TAU and PTAU, especially in terms of antioxidant enzymes. In general, differences in antiradical and antioxidant potencies between TAU and PTAU derived from in vitro test are not reliable indicators of the antioxidant potencies these compounds may subsequently manifest in a living organism.
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Affiliation(s)
- Sanket N Patel
- Department of Pharmaceutical Sciences, St. John's University, College of Pharmacy and Health Sciences, Jamaica, NY 11439, United States.
| | - Kashyap Pandya
- Department of Pharmaceutical Sciences, St. John's University, College of Pharmacy and Health Sciences, Jamaica, NY 11439, United States.
| | - George J Clark
- Department of Pharmaceutical Sciences, St. John's University, College of Pharmacy and Health Sciences, Jamaica, NY 11439, United States.
| | - Mitul C Parikh
- Department of Pharmaceutical Sciences, St. John's University, College of Pharmacy and Health Sciences, Jamaica, NY 11439, United States.
| | - Cesar A Lau-Cam
- Department of Pharmaceutical Sciences, St. John's University, College of Pharmacy and Health Sciences, Jamaica, NY 11439, United States.
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37
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Kalutharage N, Yi CS. Scope and Mechanistic Analysis for Chemoselective Hydrogenolysis of Carbonyl Compounds Catalyzed by a Cationic Ruthenium Hydride Complex with a Tunable Phenol Ligand. J Am Chem Soc 2015; 137:11105-14. [DOI: 10.1021/jacs.5b06097] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Nishantha Kalutharage
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
| | - Chae S. Yi
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
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38
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Seo SW, Song HS, Song JH, Kim GH, In I, Park CP. Microreactor mediated deoxygenation of benzylic alcohols in a biphasic organic-aqueous medium. Tetrahedron Lett 2015. [DOI: 10.1016/j.tetlet.2015.04.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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39
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40
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41
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Abstract
Bioactive natural products and derivatives remain an enduring starting point for the discovery of new cellular targets for disease intervention and lead compounds for the development of new therapeutic agents. The former goal is accomplished through the synthesis of bioactive cellular probes from natural products, enabling insights into the mechanism of action of these natural products by classical affinity chromatography or more recent proteome profiling methods. However, the direct and selective modification of native natural products for these purposes remains a challenge due to the structural complexity and the wide functional group diversity found in these natural substances. The lack of selective synthetic methods available to directly manipulate unprotected complex small molecules, in particular to perform structure-activity relationship studies and prepare appropriate cellular probes, has recently begun to be addressed, benefitting from the broader emerging area of chemoselective synthetic methodology. Thus, new reagents, catalysts and reaction processes are enabling both chemo- and site-selective modifications of complex, native natural products. In this review, we describe selected recent examples of these functionalization strategies in this emerging area.
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Affiliation(s)
- Omar Robles
- Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, USA.
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42
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43
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Abstract
Herein we report a one-pot deoxygenation protocol for primary and secondary alcohols developed via the combination of the Garegg-Samuelsson reaction, visible light-photoredox catalysis, and flow chemistry. This procedure is characterized by mild reaction conditions, easy-to-handle reactants and reagents, excellent functional group tolerance, and good yields.
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Affiliation(s)
- John D Nguyen
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA, USA
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44
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Jordan PA, Miller SJ. An approach to the site-selective deoxygenation of hydroxy groups based on catalytic phosphoramidite transfer. Angew Chem Int Ed Engl 2012; 51:2907-11. [PMID: 22319027 PMCID: PMC3319666 DOI: 10.1002/anie.201109033] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Indexed: 12/24/2022]
Affiliation(s)
- Peter A. Jordan
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT 06520-8107, Fax: (+1) 203-496-4900
| | - Scott J. Miller
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT 06520-8107, Fax: (+1) 203-496-4900
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45
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Dobmeier M, Herrmann JM, Lenoir D, König B. Reduction of benzylic alcohols and α-hydroxycarbonyl compounds by hydriodic acid in a biphasic reaction medium. Beilstein J Org Chem 2012; 8:330-6. [PMID: 22423302 PMCID: PMC3302097 DOI: 10.3762/bjoc.8.36] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 02/16/2012] [Indexed: 12/27/2022] Open
Abstract
The synthetic protocol for the reduction of alcohols to hydrocarbons by using hydriodic acid, first described by Kiliani more than 140 years ago, was improved to be more applicable to organic synthesis. Instead of a strongly acidic, aqueous solution, a biphasic toluene–water reaction medium was used, which allowed the conversion of primary, secondary and tertiary benzylic alcohols, in good yields and short reaction times, into the corresponding hydrocarbons. Red phosphorous was used as the stoichiometric reducing agent. Keto, ester, amide or ether groups are tolerated, and catalytic amounts of hydriodic acid (0.2 equiv) in the presence of 0.6 equiv phosphorous are sufficient to achieve conversion.
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Affiliation(s)
- Michael Dobmeier
- Institute of Organic Chemistry, University of Regensburg, D-93040 Regensburg, Germany
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46
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47
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Jordan PA, Miller SJ. An Approach to the Site-Selective Deoxygenation of Hydroxy Groups Based on Catalytic Phosphoramidite Transfer. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201109033] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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48
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Ryu I, Fukuyama T, Tojino M, Uenoyama Y, Yonamine Y, Terasoma N, Matsubara H. Radical carbonylation of ω-alkynylamines leading to α-methylene lactams. Synthetic scope and the mechanistic insights. Org Biomol Chem 2011; 9:3780-6. [DOI: 10.1039/c1ob05145h] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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49
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Green JC, Pettus TRR. An Oxidative Dearomatization-Induced [5 + 2] Cascade Enabling the Syntheses of α-Cedrene, α-Pipitzol, and sec-Cedrenol. J Am Chem Soc 2010; 133:1603-8. [DOI: 10.1021/ja109925g] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jason C. Green
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Thomas R. R. Pettus
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
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50
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Bietti M, Calcagni A, Salamone M. The Role of Structural Effects on the Reactions of Alkoxyl Radicals with Trialkyl and Triaryl Phosphites. A Time-Resolved Kinetic Study. J Org Chem 2010; 75:4514-20. [DOI: 10.1021/jo100703b] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Massimo Bietti
- Dipartimento di Scienze e Tecnologie Chimiche, Università “Tor Vergata”, Via della Ricerca Scientifica, 1 I-00133 Rome, Italy
| | - Alessandra Calcagni
- Dipartimento di Scienze e Tecnologie Chimiche, Università “Tor Vergata”, Via della Ricerca Scientifica, 1 I-00133 Rome, Italy
| | - Michela Salamone
- Dipartimento di Scienze e Tecnologie Chimiche, Università “Tor Vergata”, Via della Ricerca Scientifica, 1 I-00133 Rome, Italy
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