Spiroannulations of β-Ketothioamides with Bromoenals via Selective C-Michael Addition and S-Michael Addition-Triggered Cascade Reactions

J Org Chem. 2024 Oct 18;89(20):14908-14918. doi: 10.1021/acs.joc.4c01668. Epub 2024 Sep 30.

Abstract

A spiroannulation reaction of β-ketothioamides with aromatic β-bromoenals and aromatic α-bromoenals via selective C-Michael addition and S-Michael addition-triggered cascade reactions has been developed. This protocol provides a novel and rapid approach for the synthesis of substituted spirothiopyran and spirothiophene derivatives under mild conditions with moderate to good yields and a broad substrate scope.