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Andrews KG, Borsley S. Kinetic Analysis of the Redox-Neutral Catalytic Mitsunobu Reaction: Dehydration, Kinetic Barriers, and Hopping between Potential Energy Surfaces. J Am Chem Soc 2025; 147:18240-18248. [PMID: 40356305 PMCID: PMC12123607 DOI: 10.1021/jacs.5c05404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2025] [Revised: 04/30/2025] [Accepted: 05/02/2025] [Indexed: 05/15/2025]
Abstract
Denton's redox-neutral catalytic Mitsunobu reaction is remarkable in that it translates a reaction traditionally driven by the consumption of sacrificial chemical reagents to an additive-free catalytic manifold. Rational attempts to improve the system have been met with only marginal improvements, and a lack of consensus concerning the rate-determining step continues to limit effective reaction development. Here, we analyze the reaction mechanism focusing on a critical, largely overlooked element: the removal of water using a Dean-Stark apparatus. Experimental analysis of the water removal process, coupled with extensive kinetic simulations, demonstrates that the overall rate of the reaction is intimately tied to the rate of water removal. This process can be viewed as a transition between potential energy surfaces and, consequently, subsequent steps of the reaction can progress spontaneously in the absence of water, allowing an explanation of how Le Chatelier's principle, a thermodynamic effect, can have a profound kinetic influence over the rate of the reaction. We identify three bottlenecks in the reaction that inform catalyst design. Additionally, we (a) clarify the ongoing discussion regarding the rate-determining step, (b) provide clear advice concerning future reaction design taking into account the role of water and, (c) discuss the redox-neutral catalytic Mitsunobu reaction in the context of formally endergonic esterification reactions, noting parallels with ratchet mechanisms. Finally, we highlight general principles of catalyst/reaction design that emerge from our analysis and implement our findings to demonstrate a 50% rate acceleration resulting from improved water removal, a substantially greater reaction enhancement than previously obtained from computationally guided catalyst structural changes.
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Affiliation(s)
- Keith G. Andrews
- Department of Chemistry, Durham University, Lower Mount Joy, South Road, DurhamDH1 3LE, U.K.
| | - Stefan Borsley
- Department of Chemistry, Durham University, Lower Mount Joy, South Road, DurhamDH1 3LE, U.K.
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2
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Biswas A, Pradhan P, Wakpanjar SA, Kancharla PK. Direct organocatalytic esterification of carboxylic acids and alcohols by redox neutral sulfur(IV) catalysis via intramolecularly interrupted Pummerrer intermediates. Chem Commun (Camb) 2025; 61:5746-5749. [PMID: 40116732 DOI: 10.1039/d5cc00556f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2025]
Abstract
Design, synthesis, and catalytic activity of new sulfur(IV) based organocatalysts for the direct esterification of carboxylic acids and alcohols is unveiled. The polar nature of the sulfoxide in the phenol-tethered catalyst accelerates the formation of an intramolecularly interrupted Pummerrer intermediate that further facilitates the catalytic esterification reaction via the activation of carboxylic acids.
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Affiliation(s)
- Ashish Biswas
- CHEL-301, Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India.
| | - Priyanka Pradhan
- CHEL-301, Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India.
| | - Sumit Ashok Wakpanjar
- CHEL-301, Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India.
| | - Pavan K Kancharla
- CHEL-301, Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India.
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3
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Bouzina A, Aouf Z, Amira A, Bouone YO, Bentoumi H, Chemam Y, Ibrahim-Ouali M, Zerrouki R, Aouf NE. Recent Advances in the Mitsunobu and Related Reactions: A Review from 2010 to 2024. Top Curr Chem (Cham) 2025; 383:15. [PMID: 40097732 DOI: 10.1007/s41061-025-00501-3] [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: 09/18/2024] [Accepted: 02/26/2025] [Indexed: 03/19/2025]
Abstract
This review discusses recent progress in the most significant synthetic approaches involving transformations under the Mitsunobu reaction. The Mitsunobu reaction entails the "redox" condensation of an acidic pronucleophile 'Nu-H' and an electrophilic primary or secondary alcohol, facilitated by stoichiometric amounts of phosphines and azodicarboxylate reagents. Widely utilized for dehydrative oxidation-reduction condensation, this reaction shows synthetic utility through its tolerance of a broad range of acidic pronucleophiles, including carboxylic acids, pro-imides, hydroxamates, phenols, thiols, fluorinated alcohols, oximes, thioamides, pyridinium and imidazolium salts, pyrimidine bases, α-ketoesters, and trimethylmethane tricarboxylate, thereby yielding a variety of functional and potentially biologically active compounds. The purpose of this review is to focus on recent advances and applications of Mitsunobu reaction chemistry, particularly from 2010 to 2024. In addition to discussing newer reagents that facilitate purification, we will describe contemporary applications of this chemistry, especially concerning the synthesis of potential biological compounds and their precursors. This focus review of the Mitsunobu reaction summarizes its origins, the current understanding of its mechanism, and recent improvements and applications. We aim for this work to serve as a useful resource for scientists working in this research domain.
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Affiliation(s)
- Abdeslem Bouzina
- Laboratory of Applied Organic Chemistry, Bioorganic Chemistry Group, Chemistry Department, Faculty of Sciences, Badji Mokhtar-Annaba University, Box 12, 23000, Annaba, Algeria.
| | - Zineb Aouf
- Laboratory of Applied Organic Chemistry, Bioorganic Chemistry Group, Chemistry Department, Faculty of Sciences, Badji Mokhtar-Annaba University, Box 12, 23000, Annaba, Algeria
| | - Aϊcha Amira
- Laboratory of Applied Organic Chemistry, Bioorganic Chemistry Group, Chemistry Department, Faculty of Sciences, Badji Mokhtar-Annaba University, Box 12, 23000, Annaba, Algeria
- Preparatory Classes Department, National Higher School of Technology and Engineering, 23005, Annaba, Algeria
| | - Yousra Ouafa Bouone
- Laboratory of Applied Organic Chemistry, Bioorganic Chemistry Group, Chemistry Department, Faculty of Sciences, Badji Mokhtar-Annaba University, Box 12, 23000, Annaba, Algeria
| | - Houria Bentoumi
- Laboratory of Applied Organic Chemistry, Bioorganic Chemistry Group, Chemistry Department, Faculty of Sciences, Badji Mokhtar-Annaba University, Box 12, 23000, Annaba, Algeria
| | - Yasmine Chemam
- Laboratory of Applied Organic Chemistry, Bioorganic Chemistry Group, Chemistry Department, Faculty of Sciences, Badji Mokhtar-Annaba University, Box 12, 23000, Annaba, Algeria
| | | | | | - Nour-Eddine Aouf
- Laboratory of Applied Organic Chemistry, Bioorganic Chemistry Group, Chemistry Department, Faculty of Sciences, Badji Mokhtar-Annaba University, Box 12, 23000, Annaba, Algeria.
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4
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Croll EA, Kwon O. Mechanism of the Mitsunobu Reaction: An Ongoing Mystery. SYNTHESIS-STUTTGART 2024; 56:1843-1850. [PMID: 39711915 PMCID: PMC11661848 DOI: 10.1055/a-2232-8633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2024]
Abstract
The Mitsunobu reaction is one the most widely known reactions in the organic chemistry canon. Despite its fame, some aspects of the mechanism remain poorly understood, 55 years after its initial discovery. This short review collates the findings of several publications focused on the mechanism of the Mitsunobu reaction, highlighting both the current state of knowledge and the remaining missing pieces.
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Affiliation(s)
- Elizabeth A. Croll
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Ohyun Kwon
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
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5
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Ong A, Wong ZC, Chin KLO, Loh WW, Chua MH, Ang SJ, Lim JYC. Enhancing the photocatalytic upcycling of polystyrene to benzoic acid: a combined computational-experimental approach for acridinium catalyst design. Chem Sci 2024; 15:1061-1067. [PMID: 38239702 PMCID: PMC10793207 DOI: 10.1039/d3sc06388g] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 12/07/2023] [Indexed: 01/22/2024] Open
Abstract
Converting polystyrene into value-added oxygenated aromatic compounds is an attractive end-of-life upcycling strategy. However, identification of appropriate catalysts often involves laborious and time-consuming empirical screening. Herein, after demonstrating the feasibility of using acridinium salts for upcycling polystyrene into benzoic acid by photoredox catalysis for the first time, we applied low-cost descriptor-based combinatorial in silico screening to predict the photocatalytic performance of a family of potential candidates. Through this approach, we identified a non-intuitive fluorinated acridinium catalyst that outperforms other candidates for converting polystyrene to benzoic acid in useful yields at low catalyst loadings (≤5 mol%). In addition, this catalyst also proved effective with real-life polystyrene waste containing dyes and additives. Our study underscores the potential of computer-aided catalyst design for valorizing polymeric waste into essential chemical feedstock for a more sustainable future.
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Affiliation(s)
- Albert Ong
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR) 2 Fusionopolis Way, Innovis #08-03 Singapore 138634 Republic of Singapore
| | - Zi Cheng Wong
- Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR) 1 Fusionopolis Way, Connexis, #16-16 Singapore 138632 Republic of Singapore
| | - Kang Le Osmund Chin
- Institute of Sustainability for Chemicals, Energy and Environment (ISCE2), Agency for Science, Technology and Research (A*STAR) 1 Pesek Road, Jurong Island Singapore 627833 Republic of Singapore
| | - Wei Wei Loh
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR) 2 Fusionopolis Way, Innovis #08-03 Singapore 138634 Republic of Singapore
| | - Ming Hui Chua
- Institute of Sustainability for Chemicals, Energy and Environment (ISCE2), Agency for Science, Technology and Research (A*STAR) 1 Pesek Road, Jurong Island Singapore 627833 Republic of Singapore
| | - Shi Jun Ang
- Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR) 1 Fusionopolis Way, Connexis, #16-16 Singapore 138632 Republic of Singapore
- Institute of Sustainability for Chemicals, Energy and Environment (ISCE2), Agency for Science, Technology and Research (A*STAR) 1 Pesek Road, Jurong Island Singapore 627833 Republic of Singapore
| | - Jason Y C Lim
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR) 2 Fusionopolis Way, Innovis #08-03 Singapore 138634 Republic of Singapore
- Department of Materials Science and Engineering, National University of Singapore (NUS) 9 Engineering Drive 1 Singapore 117576 Republic of Singapore
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Chen T, Mei Y, Liu LL, Zhao Y, Wu Y, Stephan DW. Alkoxyphosphorane/Borane Cooperative Alkylations: A Frustrated Lewis Pair Version of the Mitsunobu Reaction. Chemistry 2023; 29:e202300264. [PMID: 36715454 DOI: 10.1002/chem.202300264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 01/27/2023] [Accepted: 01/30/2023] [Indexed: 01/31/2023]
Abstract
The combination of the alkoxyphosphoranes, Ph2 P(OR)(O2 C6 Cl4 ) and the borane B(C6 F5 )3 generates the zwitterions 3 which act as FLP to effect the alkylation of several nucleophiles affording C-C, C-N, C-H and C-Cl coupling products. A DFT study shows the reaction proceeds via an FLP activation pathway generating an alkoxyphosphonium intermediate which effects the alkylation of the nucleophiles, akin to the Mitsunobu reaction.
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Affiliation(s)
- Ting Chen
- Institute of Drug Discovery Technology, Ningbo University, 315211, Ningbo, Zhejiang, P. R. China
| | - Yanbo Mei
- Department of Chemistry and, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, 518055, Shenzhen, P. R. China
| | - Liu Leo Liu
- Department of Chemistry and, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, 518055, Shenzhen, P. R. China
| | - Yufen Zhao
- Institute of Drug Discovery Technology, Ningbo University, 315211, Ningbo, Zhejiang, P. R. China
| | - Yile Wu
- Institute of Drug Discovery Technology, Ningbo University, 315211, Ningbo, Zhejiang, P. R. China
| | - Douglas W Stephan
- Institute of Drug Discovery Technology, Ningbo University, 315211, Ningbo, Zhejiang, P. R. China.,Department of Chemistry, University of Toronto, 80 St. George St, M5S3H6, Toronto, ON, Canada
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Patel B, Dabas S, Patel P, Subramanian S. Electrostatically tuned phenols: a scalable organocatalyst for transfer hydrogenation and tandem reductive alkylation of N-heteroarenes. Chem Sci 2023; 14:540-549. [PMID: 36741513 PMCID: PMC9847667 DOI: 10.1039/d2sc05843j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022] Open
Abstract
One of the fundamental aims in catalysis research is to understand what makes a certain scaffold perform better as a catalyst than another. For instance, in nature enzymes act as versatile catalysts, providing a starting point for researchers to understand how to achieve superior performance by positioning the substrate close to the catalyst using non-covalent interactions. However, translating this information to a non-biological catalyst is a challenging task. Here, we report a simple and scalable electrostatically tuned phenol (ETP) as an organocatalyst for transfer hydrogenation of N-arenes using the Hantzsch ester as a hydride source. The biomimetic catalyst (1-5 mol%) displays potential catalytic activity to prepare diverse tetrahydroquinoline derivatives with good to excellent conversion under ambient reaction conditions. Kinetic studies reveal that the ETP is 130-fold faster than the uncharged counterpart, towards completion of the reaction. Control experiments and NMR spectroscopic investigations elucidate the role of the charged environment in the catalytic transformation.
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Affiliation(s)
- Brijesh Patel
- Inorganic Materials and Catalysis Division, CSIR – Central Salt & Marine Chemicals Research InstituteBhavnagar-364002GujaratIndia,Academy of Scientific and Innovative Research (AcSIR)Gaziabad-201002India
| | - Shilpa Dabas
- Inorganic Materials and Catalysis Division, CSIR – Central Salt & Marine Chemicals Research InstituteBhavnagar-364002GujaratIndia,Academy of Scientific and Innovative Research (AcSIR)Gaziabad-201002India
| | - Parth Patel
- Inorganic Materials and Catalysis Division, CSIR – Central Salt & Marine Chemicals Research InstituteBhavnagar-364002GujaratIndia,Academy of Scientific and Innovative Research (AcSIR)Gaziabad-201002India
| | - Saravanan Subramanian
- Inorganic Materials and Catalysis Division, CSIR – Central Salt & Marine Chemicals Research InstituteBhavnagar-364002GujaratIndia,Academy of Scientific and Innovative Research (AcSIR)Gaziabad-201002India
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8
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Hergueta AR. Easy Removal of Triphenylphosphine Oxide from Reaction Mixtures by Precipitation with CaBr 2. Org Process Res Dev 2022. [DOI: 10.1021/acs.oprd.2c00104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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9
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Phenolic 3° Phosphine Oxides as a Class of Metal-Free Catalysts for the Activation of C–O Bonds in Aliphatic Alcohols: Direct Synthesis of Catalyst Candidates, and Kinetic Studies. INORGANICS 2022. [DOI: 10.3390/inorganics10030035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
It was recently reported that a (2-hydroxybenzyl)phosphine oxide (2-HOBPO) can serve as a phosphorus-centered catalyst for the stereo-invertive coupling of aliphatic alcohols and acidic pronucleophiles (akin to a Mitsunobu reaction, but without additional reagents). Herein, we report an improved synthesis, which provides direct access to systematically varied 2-HOBPOs in a single step from commercially available precursors (salicylaldehydes and secondary phosphines). The efficiency and generality of the synthetic method enabled limited structure–activity relationship (SAR) studies, from which it was determined that substituents on both the phenolic and phosphine oxide portions can exert significant influence on the turnover frequency (TOF) of each catalyst. Importantly, for all catalytically active 2-HOBPOs examined, the molecularity of catalyst in the rate law of the alcohol coupling was determined to be <1. Thus, for high catalyst loadings, differences in catalytic activity between 2-HOBPOs appear to be dominated by differences in catalytic auto-inhibition, while for low catalyst loadings, differences are attributed to inherent differences in the energetic span of the catalytic cycle, ignoring off-cycle species, in good agreement with density functional theory (DFT) modeling at the ωB97X-D/6-311G(d,p) level.
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10
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Glueck DS. Intramolecular attack on coordinated nitriles: metallacycle intermediates in catalytic hydration and beyond. Dalton Trans 2021; 50:15953-15960. [PMID: 34643205 DOI: 10.1039/d1dt02795f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydration of nitriles is catalyzed by the enzyme nitrile hydratase, with iron or cobalt active sites, and by a variety of synthetic metal complexes. This Perspective focuses on parallels between the reaction mechanism of the enzyme and a class of particularly active catalysts bearing secondary phosphine oxide (SPO) ligands. In both cases, the key catalytic step was proposed to be intramolecular attack on a coordinated nitrile, with either an S-OH or S-O- (enzyme) or a P-OH (synthetic) nucleophile. Attack of water on the heteroatom (S or P) in the resulting metallacycle and proton transfer yields the amide and regenerates the catalyst. Evidence for this mechanism, its relevance to the formation of related metallacycles, and its potential for design of more active catalysts for nitrile hydration is summarized.
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Affiliation(s)
- David S Glueck
- 6128 Burke Laboratory, Department of Chemistry, Dartmouth College, Hanover, New Hampshire, 03755, USA.
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11
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Ma X, Chiou MF, Ge L, Li X, Li Y, Wu L, Bao H. Iron phthalocyanine-catalyzed radical phosphinoylazidation of alkenes: A facile synthesis of β-azido-phosphine oxide with a fast azido transfer step. CHINESE JOURNAL OF CATALYSIS 2021. [DOI: 10.1016/s1872-2067(21)63847-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Abstract
Computational methods have emerged as a powerful tool to augment traditional experimental molecular catalyst design by providing useful predictions of catalyst performance and decreasing the time needed for catalyst screening. In this perspective, we discuss three approaches for computational molecular catalyst design: (i) the reaction mechanism-based approach that calculates all relevant elementary steps, finds the rate and selectivity determining steps, and ultimately makes predictions on catalyst performance based on kinetic analysis, (ii) the descriptor-based approach where physical/chemical considerations are used to find molecular properties as predictors of catalyst performance, and (iii) the data-driven approach where statistical analysis as well as machine learning (ML) methods are used to obtain relationships between available data/features and catalyst performance. Following an introduction to these approaches, we cover their strengths and weaknesses and highlight some recent key applications. Furthermore, we present an outlook on how the currently applied approaches may evolve in the near future by addressing how recent developments in building automated computational workflows and implementing advanced ML models hold promise for reducing human workload, eliminating human bias, and speeding up computational catalyst design at the same time. Finally, we provide our viewpoint on how some of the challenges associated with the up-and-coming approaches driven by automation and ML may be resolved.
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Affiliation(s)
- Ademola Soyemi
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL 35487, USA.
| | - Tibor Szilvási
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL 35487, USA.
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13
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Kasama K. Redox-neutral Mitsunobu Reaction. J SYN ORG CHEM JPN 2021. [DOI: 10.5059/yukigoseikyokaishi.79.344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Kengo Kasama
- Graduate School of Pharmaceutical Sciences, Osaka University
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