Me₃SiCF₂Br-Self-Assisted Domino Reaction: Catalytic Synthesis of α,α-Difluorocyclopentanones from Methylvinylketones

Abstract

A complete self-assistance strategy based on Me₃SiCF₂Br was used in the domino conversion of methylvinylketones into α,α-difluorinated cyclopentanones. Initiated by 5 mol % of nBu₄NBr, the multistep reaction occurred in one pot under mild conditions via the in situ formation of silyl dienol ethers, difluorocyclopropanation, thermal vinylcyclopropane-cyclopentene rearrangement, and desilylation. The process takes advantage of the multitasking capability of Me₃SiCF₂Br as the difluorocarbene source, a silicon-based transfer agent, and a bromine anion releaser.