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

• 2,2-Difluoro-γ-ketoesters are prepared from enol acetates.
• ClSO2CF2CO2Me is used as a source of MeO2CCF2 radicals.
• Photoredox catalysis is used to carry out carbomethoxydifluoromethylation of enol acetates.

In a visible light, room temperature photoredox catalytic process using 0.5 mol% of a Ir[(dF(CF3)ppy)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-γ-ketoesters in moderate to very good yields.

Figure optionsDownload as PowerPoint slide