An unconventional synthetic pathway for the reaction of alkynyl sulfonium ylides with aromatic acid anhydrides leading to the formation of sulfonium diacylmethylide frameworks

Abstract

Here, we demonstrate an unconventional synthetic pathway for the reaction of alkynyl sulfonium ylides with aromatic acid anhydrides, leading to the remarkable generation of sulfonium diacylmethylide frameworks. In reactions with cyclic aromatic acid anhydrides, the alkynyl group of alkynyl sulfonium ylides uniquely functions as a leaving group, which is the first such reported example, affording sulfonium diacylmethylide derivatives. In contrast, reactions with non-cyclic aromatic acid anhydrides involve isomerization of the alkynyl group to generate an allenic intermediate, which subsequently furnishes sulfonium diacylmethylide products. The reaction mechanisms for both cyclic and non-cyclic aromatic acid anhydrides were elucidated by in situ HRMS analysis and isotope labeling experiments, respectively. This strategy features mild reaction conditions, moderate to high yields, and broad substrate scope for the preparation of sulfonium diacylmethylide motifs.