Transition-Metal-Free Carbonyl Reduction and Hydrodefluorination of β-Trifluoromethyl Enones with Hydrosilanes: Synthesis of gem-Difluorovinyl Alcohols

A tandem carbonyl reduction and hydrodefluorination of β-trifluoromethyl enones with hydrosilanes under transition-metal-free conditions was developed for the synthesis of a variety of valuable gem-difluorovinyl alcohols. The hydrosilane could act as both a reductive agent and a C(sp³)-F bond-breaking promoter under mild reaction conditions. Synthetically useful organofluorides, such as gem-fluorophosphine alkene, gem-difluorovinyl ketone, and fluorinated dihydrofuran derivatives could be readily constructed by further transformations of the obtained gem-difluorovinyl alcohols. Moreover, the method features mild reaction conditions, operational simplicity, excellent functional group tolerance, and scalability.