Yuan T, Ryckaert B, Van Hecke K, Hullaert J, Winne JM. Stereoselective Gold(I)-Catalyzed Vinylcyclopropanation via Generation of a Sulfur-Substituted Vinyl Carbene Equivalent.
Angew Chem Int Ed Engl 2021;
60:4070-4074. [PMID:
33169902 DOI:
10.1002/anie.202012664]
[Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/22/2020] [Indexed: 01/27/2023]
Abstract
A stereoselective gold(I)-catalyzed vinylcyclopropanation of alkenes has been developed. A gold-coordinated cationic vinyl carbene species, readily generated via a rearrangement of the ethylenedithioacetal of propargyl aldehyde, reacts with a wide range of alkenes to afford thio-substituted vinylcyclopropanes. The gold-catalyzed vinyl cyclopropanation proceeds under mild conditions at room temperature and is generally selective for the formation of cis-substituted cyclopropanes. The reaction allows the formal introduction of a "naked" vinyl carbene, by subsequent chemoselective hydrodesulfurisation of the ethylenedithio-bridge. The synthetic utility of the new method is demonstrated by a short, racemic formal synthesis of the alkaloid cephalotaxin, hinging on a key vinyl cyclopropane-cyclopentene rearrangement.
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