Nam DG, Shim SY, Jeong HM, Ryu DH. Catalytic Asymmetric Darzens-Type Epoxidation of Diazoesters: Highly Enantioselective Synthesis of Trisubstituted Epoxides.
Angew Chem Int Ed Engl 2021;
60:22236-22240. [PMID:
34350688 DOI:
10.1002/anie.202108454]
[Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/19/2021] [Indexed: 12/24/2022]
Abstract
Highly enantioselective Darzens-type epoxidation of diazoesters with glyoxal derivatives was accomplished using a chiral boron-Lewis acid catalyst, which facilitated asymmetric synthesis of trisubstituted α,β-epoxy esters. In the presence of a chiral oxazaborolidinium ion catalyst, the reaction proceeded in high yield (up to 99 %) with excellent enantio- and diastereoselectivity (up to >99 % ee and >20:1 dr, respectively). The synthetic potential of this method was illustrated by conversion of the products to various compounds such as epoxy γ-butyrolactone, tertiary β-hydroxy ketone and epoxy diester.
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