Asymmetric Isochalcogenourea-Catalyzed Synthesis of 3,4-Dihydropyrans via (4+2)-Cycloadditions of Ethyl But-3-ynoate with Michael Acceptors

Abstract

We herein report the use of ethyl but-3-ynoate as a C2 building block for asymmetric (4+2)-heterocycloadditions with various Michael acceptors. Upon using chiral isochalcogenoureas as Lewis base catalysts, these reactions can be carried out with good-to-excellent control of the regioselectivity, diastereoselectivity, and enantioselectivity.

Keywords

Organocatalysis - Lewis bases - Isochalcogenoureas - Cycloadditions - Alkynes - Heterocycles

Publication History

Received: 23 May 2025

Accepted after revision: 18 July 2025

Accepted Manuscript online:
18 July 2025

Article published online:
18 August 2025

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