The merger of decatungstate and copper catalysis to enable aliphatic C(sp3)–H trifluoromethylation

The introduction of a trifluoromethyl (CF3) group can dramatically improve a compound’s biological properties. Despite the well-established importance of trifluoromethylated compounds, general methods for the trifluoromethylation of alkyl C–H bonds remain elusive. Here we report the development of a dual-catalytic C(sp3)–H trifluoromethylation through the merger of light-driven, decatungstate-catalysed hydrogen atom transfer and copper catalysis. This metallaphotoredox methodology enables the direct conversion of both strong aliphatic and benzylic C–H bonds into the corresponding C(sp3)–CF3 products in a single step using a bench-stable, commercially available trifluoromethylation reagent. The reaction requires only a single equivalent of substrate and proceeds with excellent selectivity for positions distal to unprotected amines. To demonstrate the utility of this new methodology for late-stage functionalization, we have directly derivatized a broad range of approved drugs and natural products to generate valuable trifluoromethylated analogues. Preliminary mechanistic experiments reveal that a ‘Cu–CF3’ species is formed during this process and the critical C(sp3)–CF3 bond-forming step involves the copper catalyst. Despite the importance of trifluoromethylated compounds, direct catalytic methods for the conversion of C(sp3)–H bonds into the corresponding C(sp3)–CF3 analogues have remained elusive. This transformation has now been achieved by the merger of copper catalysis with decatungstate photocatalysis, enabling the C(sp3)–H trifluoromethylation of abundant feedstocks, natural products and pharmaceuticals.