Gold-Catalyzed Reaction of Propargyl Esters and Alkynylsilanes: Synthesis of Vinylallene Derivatives through a Twofold 1,2-Rearrangement

The reaction of propargyl esters with alkynylsilanes under gold catalysis provides vinylallene derivatives through consecutive [1,2]-acyloxy/[1,2]-silyl rearrangements. Good yields, full atom-economy, broad substrate scope, easy scale-up and low catalyst loadings are salient features of this novel transformation. Density Functional Theory (DFT) calculations suggest a reaction mechanism involving initial [1,2]-acyloxy rearrangement to generate a gold vinylcarbene intermediate which upon regioselective attack of the alkynylsilane affords a vinyl cation which undergoes a type II-dyotropic rearrangement involving the silyl group and the metal fragment. Preliminary results on the enantioselective version of this transformation are also disclosed.

Automated summary

The gold-catalyzed reaction of propargyl esters with alkynylsilanes produces vinylallene derivatives through consecutive [1,2]-acyloxy/[1,2]-silyl rearrangements. This transformation features good yields, full atom-economy, a broad substrate scope, easy scale-up, and low catalyst loadings. The reaction mechanism involves the generation of a gold vinylcarbene intermediate and a type II-Dyotropic rearrangement involving the silyl group and the metal fragment.