Chromium-catalyzed allylic defluorinative acylation of trifluoromethyl-substituted alkenes with acyl oxime esters

Abstract

Herein we report a chromium-catalyzed reductive allylic defluorinative acylation of trifluoromethyl substituted alkenes with acyl oxime esters as the acylating agents, allowing for efficient synthesis of various ketones bearing a gem-difluoroalkene unit. The preliminary mechanistic investigations reveal that low-valent chromium species promote both the reduction of acyl oxime esters and the rate-limiting β-fluoro elimination while the additive potassium phosphate suppresses the undesired hydroacylation side reaction.