Base-controlled selective cleavage of the C–F bond of difluorocarbene for the divergent assembly of indolizines

Abstract

A [3 + 1 + 1] cascade annulation reaction for the divergent construction of trisubstituted indolizines using sulfoxonium ylides, BrCF₂CO₂Me and pyridinium salts as readily available substrates has been developed. By changing the reaction conditions, this metal-free process realized selective cleavage of one or two C–F bonds of difluorocarbene and let it act as a C or CF source. Further transformation of the product presented the practicality of this reaction.