Carbomethoxydifluoromethylation of enol acetates with methyl (chlorosulfonyl)difluoroacetate using visible-light photoredox catalysis. Synthesis of 2,2-difluoro-γ-ketoesters

In a visible light, room temperature photoredox catalytic process using 0.5 mol% of a Ir[(dF(CF3)p-py)(2)(dtbbpy)]PF6 catalyst, a general method for attaching a carbomethoxydifluoromethyl group to the alpha position of a ketone, using the reaction of methyl (chlorosulfonyl)difluoroacetate (MCDA) with enol acetates, is reported. This method allows the synthesis of a variety of 2,2-difluoro-gamma-ketoesters in moderate to very good yields. (C) 2015 Elsevier B.V. All rights reserved.