Photomediated C–H trifluoromethoxylations enabled by bis(trifluoromethyl)peroxide

Abstract

We describe a photomediated protocol for the trifluoromethoxylation of benzylic, aldehydic, and non-activated C–H bonds, using bis(trifluoromethyl)peroxide (BTMP, (F₃CO)₂) as the key reagent. Under catalyst-free conditions in acetone, this reaction proceeds with selective functionalization of benzylic methylene groups. Furthermore, by using tetrabutylammonium decatungstate as a photocatalyst, the scope extends to include both non-activated methylene C(sp³)–H and formyl C(sp²)–H bonds. The methodology was successfully applied to 24 examples including odorants, pharmaceuticals, and natural products and was demonstrated on gram scale. Finally, by using [¹³C]-BTMP, the corresponding trifluoromethoxy groups can be site-specifically labeled with ¹³C.