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Yisimayili N, Li ZF, Liu T, Lu CD. Stereoselective Electrophilic Sulfenylation of β,β-Disubstituted Enesulfinamides: Asymmetric Construction of Less Accessible Acyclic α,α-Disubstituted α-Sulfenylated Ketimines. Org Lett 2024; 26:5978-5983. [PMID: 38967298 DOI: 10.1021/acs.orglett.4c02030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/06/2024]
Abstract
Current methods for the asymmetric α-sulfenylation of carbonyls cannot be applied to acyclic carbonyls that have two similar substituents at the α-position. This research demonstrated that the electrophilic sulfenylation of geometry-defined acyclic β,β-disubstituted enesulfinamides using S-aryl or S-alkyl benzenethiosulfonates can be highly stereoselective. This process results in enantioenriched α,α-disubstituted α-sulfenylated ketone surrogates with sulfur-containing acyclic tetrasubstituted carbon stereocenters bearing two electronically and sterically similar substituents (e.g., methyl and ethyl). Furthermore, by employing the corresponding stereoisomers of enensulfinamides, any of the four stereoisomers of α-sulfenylated ketimines can be selectively accessed.
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Affiliation(s)
| | - Zheng-Fei Li
- School of Chemical Science and Technology, Yunnan University, Kunming, Yunnan 650091, China
| | - Tao Liu
- School of Chemical Science and Technology, Yunnan University, Kunming, Yunnan 650091, China
| | - Chong-Dao Lu
- School of Chemical Science and Technology, Yunnan University, Kunming, Yunnan 650091, China
- School of Health, Jiangxi Normal University, Nanchang, Jiangxi 330022, China
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Xiong TZ, Yisimayili N, Lu CD. Stereoselective Electrophilic Chlorination of β,β-Disubstituted Enesulfinamides with Chloramine-T: Asymmetric Synthesis of Acyclic α,α-Disubstituted α-Chlorinated Carbonyl Surrogates. Org Lett 2024; 26:1851-1856. [PMID: 38386702 DOI: 10.1021/acs.orglett.4c00059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
Enamine and iminium ion-mediated asymmetric organocatalysis was not successful in achieving highly stereoselective α-chlorination of acyclic α,α-disubstituted carbonyls. To address this limitation, an alternative method was developed, which involved the use of geometry-defined persubstituted enesulfinamides to intercept the electrophilic chlorinating reagent. This approach enables the asymmetric construction of challenging acyclic α,α-disubstituted α-chlorinated ketimines with a high degree of stereoselectivity. The use of chloramine-T, a cost-effective and stable chlorine source rarely utilized in asymmetric electrophilic chlorination, plays a crucial role in achieving superior stereocontrol.
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Affiliation(s)
- Teng-Zhao Xiong
- School of Chemical Science and Technology, Yunnan University, Kunming, Yunnan 650091, China
| | | | - Chong-Dao Lu
- School of Chemical Science and Technology, Yunnan University, Kunming, Yunnan 650091, China
- School of Health, Jiangxi Normal University, Nanchang, Jiangxi 330022, China
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Vera S, Landa A, Mielgo A, Ganboa I, Oiarbide M, Soloshonok V. Catalytic Asymmetric α-Functionalization of α-Branched Aldehydes. Molecules 2023; 28:molecules28062694. [PMID: 36985666 PMCID: PMC10056299 DOI: 10.3390/molecules28062694] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 03/14/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023] Open
Abstract
Aldehydes constitute a main class of organic compounds widely applied in synthesis. As such, catalyst-controlled enantioselective α-functionalization of aldehydes has attracted great interest over the years. In this context, α-branched aldehydes are especially challenging substrates because of reactivity and selectivity issues. Firstly, the transient trisubstituted enamines and enolates resulting upon treatment with an aminocatalyst or a base, respectively, would exhibit attenuated reactivity; secondly, mixtures of E- and Z-configured enamines/enolates may be formed; and third, effective face-discrimination on such trisubstituted sp2 carbon intermediates by the incoming electrophilic reagent is not trivial. Despite these issues, in the last 15 years, several catalytic approaches for the α-functionalization of prostereogenic α-branched aldehydes that proceed in useful yields and diastereo- and enantioselectivity have been uncovered. Developments include both organocatalytic and metal-catalyzed approaches as well as dual catalysis strategies for forging new carbon–carbon and carbon–heteroatom (C-O, N, S, F, Cl, Br, …) bond formation at Cα of the starting aldehyde. In this review, some key early contributions to the field are presented, but focus is on the most recent methods, mainly covering the literature from year 2014 onward.
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Affiliation(s)
- Silvia Vera
- Department of Organic Chemistry I, University of the Basque Country UPV/EHU, Manuel Lardizabal 3, 20018 Donostia-San Sebastián, Spain
| | - Aitor Landa
- Department of Organic Chemistry I, University of the Basque Country UPV/EHU, Manuel Lardizabal 3, 20018 Donostia-San Sebastián, Spain
| | - Antonia Mielgo
- Department of Organic Chemistry I, University of the Basque Country UPV/EHU, Manuel Lardizabal 3, 20018 Donostia-San Sebastián, Spain
- Correspondence: (A.M.); (M.O.)
| | - Iñaki Ganboa
- Department of Organic Chemistry I, University of the Basque Country UPV/EHU, Manuel Lardizabal 3, 20018 Donostia-San Sebastián, Spain
| | - Mikel Oiarbide
- Department of Organic Chemistry I, University of the Basque Country UPV/EHU, Manuel Lardizabal 3, 20018 Donostia-San Sebastián, Spain
- Correspondence: (A.M.); (M.O.)
| | - Vadim Soloshonok
- Department of Organic Chemistry I, University of the Basque Country UPV/EHU, Manuel Lardizabal 3, 20018 Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Spain
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