Radical C(sp2)-H Trifluoromethylation of Aldehydes in Aqueous Solution.

The copper-mediated C(sp2)-H trifluoromethylation of aldehydes is described. The reaction of aldehydes with (bpy)Cu(CF3)3, Et3SiH, and K2S2O8 in aqueous acetone at room temperature provides the corresponding trifluoromethyl ketones in satisfactory yields. The protocol is applicable to both aliphatic and aromatic aldehydes and exhibits a broad substrate scope and wide functional group compatibility. A mechanism involving Cu(II)-mediated trifluoromethylation of acyl radicals is proposed.