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Liu J, Ma J, Wang T, Xue XS, Zhu C. Radical-Mediated α- tert-Alkylation of Aldehydes by Consecutive 1,4- and 1,3-(Benzo)thiazolyl Migrations. JACS AU 2024; 4:2108-2114. [PMID: 38938795 PMCID: PMC11200231 DOI: 10.1021/jacsau.4c00322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/21/2024] [Accepted: 05/22/2024] [Indexed: 06/29/2024]
Abstract
The direct alkylation of the α-position of aldehydes is an effective method for accessing a wide range of structurally diverse aldehydes, yet tert-alkylation has proven to be a challenging task. In this study, we present a novel radical-mediated tert-alkylation approach targeting the α-position of aldehydes, enabling the synthesis of complex aliphatic aldehydes. The transformation is initiated by the interaction between an in situ generated enamine intermediate and α-bromo sulfone, forming an electron donor-acceptor (EDA) complex, followed by consecutive 1,4- and 1,3-functional group migrations. This protocol operates under metal-free and mild photochemical conditions, delivering a broad scope of products and providing new mechanistic insights into radical rearrangement reactions.
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Affiliation(s)
- Jige Liu
- Frontiers
Science Center for Transformative Molecules, Zhangjiang Institute
for Advanced Study, and Shanghai Key Laboratory for Molecular Engineering
of Chiral Drugs, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
- Key
Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry,
Chemical Engineering and Materials Science, Soochow University, 199 Ren-Ai Road, Suzhou, Jiangsu 215123, China
| | - Jiangshan Ma
- Frontiers
Science Center for Transformative Molecules, Zhangjiang Institute
for Advanced Study, and Shanghai Key Laboratory for Molecular Engineering
of Chiral Drugs, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Tongkun Wang
- Key
Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials, Shanghai Institute of Organic Chemistry, University
of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Xiao-Song Xue
- Key
Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials, Shanghai Institute of Organic Chemistry, University
of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Chen Zhu
- Frontiers
Science Center for Transformative Molecules, Zhangjiang Institute
for Advanced Study, and Shanghai Key Laboratory for Molecular Engineering
of Chiral Drugs, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
- Key
Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry,
Chemical Engineering and Materials Science, Soochow University, 199 Ren-Ai Road, Suzhou, Jiangsu 215123, China
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Hensinger MJ, Eitzinger A, Trapp O, Ofial AR. Nucleophilicity of 4-(Alkylthio)-3-imidazoline Derived Enamines. Chemistry 2024; 30:e202302764. [PMID: 37850416 PMCID: PMC10962604 DOI: 10.1002/chem.202302764] [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: 08/23/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 10/19/2023]
Abstract
Imidazolidine-4-thiones (ITOs) are cyclic, secondary amines that were considered as potential prebiotic organocatalysts for light-driven α-alkylations of aldehydes by bromoacetonitrile (BAN). Recent studies showed that the initially supplied ITOs represent the pre-catalyst because they undergo S-alkylation with BAN to give 4-(alkylthio)-3-imidazolines (TIMs). Given that the same reagent mix that undergoes light-driven α-alkylations is also effective in the dark, we synthesized ten ITO- or TIM-derived enamines of aldehydes and characterized their nucleophilic reactivities by kinetic studies in acetonitrile. The experimental second-order rate constants k2 for reactions of enamines with benzhydrylium ions (reference electrophiles) were evaluated by the Mayr-Patz equation, lg k2 (20 °C)=sN (N+E). The determined nucleophilicities N (and sN ) reveal the reactivity profiles of these enamines under prebiotically relevant conditions as well as their potential for use in organocatalytic synthesis.
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Affiliation(s)
- Magenta J. Hensinger
- Department ChemieLudwig-Maximilians-Universtität MünchenButenandtstrasse 5–1381377MünchenGermany
| | - Andreas Eitzinger
- Department ChemieLudwig-Maximilians-Universtität MünchenButenandtstrasse 5–1381377MünchenGermany
| | - Oliver Trapp
- Department ChemieLudwig-Maximilians-Universtität MünchenButenandtstrasse 5–1381377MünchenGermany
- Max-Planck-Institute for AstronomyKönigstuhl 1769117HeidelbergGermany
| | - Armin R. Ofial
- Department ChemieLudwig-Maximilians-Universtität MünchenButenandtstrasse 5–1381377MünchenGermany
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Theoretical Study on the Origin of Abnormal Regioselectivity in Ring-Opening Reaction of Hexafluoropropylene Oxide. Molecules 2023; 28:molecules28041669. [PMID: 36838653 PMCID: PMC9962681 DOI: 10.3390/molecules28041669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/19/2023] [Accepted: 02/01/2023] [Indexed: 02/12/2023] Open
Abstract
That nucleophiles preferentially attack at the less sterically hindered carbon of epoxides under neutral and basic conditions has been generally accepted as a fundamental rule for predicting the regioselectivity of this type of reaction. However, this rule does not hold for perfluorinated epoxides, such as hexafluoropropylene oxide (HFPO), in which nucleophiles were found to attack at the more hindered CF3 substituted β-C rather than the fluorine substituted α-C. In this contribution, we aim to shed light on the nature of this intriguing regioselectivity by density functional theory methods. Our calculations well reproduced the observed abnormal regioselectivities and revealed that the unusual regiochemical preference for the sterically hindered β-C of HFPO mainly arises from the lower destabilizing distortion energy needed to reach the corresponding ring-opening transition state. The higher distortion energy required for the attack of the less sterically hindered α-C results from a significant strengthening of the C(α)-O bond by the negative hyperconjugation between the lone pair of epoxide O atom and the antibonding C-F orbital.
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Computational insights into the effects of reagent structure and bases on nucleophilic monofluoromethylation of aldehydes. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2021.11.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abstract
The fields of C-H functionalization and photoredox catalysis have garnered enormous interest and utility in the past several decades. Many different scientific disciplines have relied on C-H functionalization and photoredox strategies including natural product synthesis, drug discovery, radiolabeling, bioconjugation, materials, and fine chemical synthesis. In this Review, we highlight the use of photoredox catalysis in C-H functionalization reactions. We separate the review into inorganic/organometallic photoredox catalysts and organic-based photoredox catalytic systems. Further subdivision by reaction class─either sp2 or sp3 C-H functionalization─lends perspective and tactical strategies for use of these methods in synthetic applications.
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Affiliation(s)
- Natalie Holmberg-Douglas
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - David A Nicewicz
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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Mondal S, Dumur F, Gigmes D, Sibi MP, Bertrand MP, Nechab M. Enantioselective Radical Reactions Using Chiral Catalysts. Chem Rev 2022; 122:5842-5976. [DOI: 10.1021/acs.chemrev.1c00582] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Shovan Mondal
- Department of Chemistry, Syamsundar College, Shyamsundar 713424, West Bengal, India
| | - Frédéric Dumur
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, F-13390e Marseille, France
| | - Didier Gigmes
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, F-13390e Marseille, France
| | - Mukund P. Sibi
- Department of Chemistry and Biochemistry North Dakota State University, Fargo, North Dakota 58108, United States
| | - Michèle P. Bertrand
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, F-13390e Marseille, France
| | - Malek Nechab
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, F-13390e Marseille, France
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Yao W, Bergamino EAB, Ngai MY. Asymmetric Photocatalysis Enabled by Chiral Organocatalysts. ChemCatChem 2022; 14:e202101292. [PMID: 36204304 PMCID: PMC9531867 DOI: 10.1002/cctc.202101292] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Indexed: 01/12/2023]
Abstract
Visible-light photocatalysis has advanced as a versatile tool in organic synthesis. However, attaining precise stereocontrol in photocatalytic reactions has been a longstanding challenge due to undesired photochemical background reactions and the involvement of highly reactive radicals or radical ion intermediates generated under photocatalytic conditions. To address this problem and expand the synthetic utility of photocatalytic reactions, a number of innovative strategies, including mono- and dual-catalytic approaches, have recently emerged. Of these, exploiting chiral organocatalysis, such as enamine catalysis, iminium-ion catalysis, Brønsted acid/base catalysis, and N-heterocyclic carbene catalysis, to induce chirality transfer of photocatalytic reactions has been widely explored. This Review aims to provide a current, comprehensive overview of asymmetric photocatalytic reactions enabled by chiral organocatalysts published through June 2021. The substrate scope, advantages, limitations, and proposed reaction mechanisms of each reaction are discussed. This review should serve as a reference for the development of visible-light-induced asymmetric photocatalysis and promote the improvement of the chemical reactivity and stereoselectivity of these reactions.
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Affiliation(s)
- Wang Yao
- Department of Chemistry, the State University of New York at Stony Brook, Stony Brook, New York, 11794
| | | | - Ming-Yu Ngai
- Department of Chemistry, the State University of New York at Stony Brook, Stony Brook, New York, 11794
- Institute of Chemical Biology and Drug Discovery, the State University of New York at Stony Brook, Stony Brook, New York 11794
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Organocatalysis Combined with Photocatalysis. Top Curr Chem (Cham) 2019; 377:37. [DOI: 10.1007/s41061-019-0265-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 11/01/2019] [Indexed: 12/11/2022]
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Naesborg L, Leth LA, Reyes-Rodríguez GJ, Palazzo TA, Corti V, Jørgensen KA. Direct Enantio- and Diastereoselective Oxidative Homocoupling of Aldehydes. Chemistry 2018; 24:14844-14848. [DOI: 10.1002/chem.201803506] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Line Naesborg
- Department of Chemistry; Aarhus University; 8000 Aarhus Denmark
| | - Lars A. Leth
- Department of Chemistry; Aarhus University; 8000 Aarhus Denmark
| | | | | | - Vasco Corti
- Department of Chemistry; Aarhus University; 8000 Aarhus Denmark
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