Electrophotocatalytic Undirected C-H Trifluoromethylations of (Het)Arenes.

Youai Qiu,Lutz Ackermann,Alexej Scheremetjew,Lars H Finger

doi:10.1002/chem.201905774

Abstract

Electrophotochemistry has enabled arene C−H trifluoromethylation with the Langlois reagent CF3SO2Na under mild reaction conditions. The merger of electrosynthesis and photoredox catalysis provided a chemical oxidant‐free approach for the generation of the CF3 radical. The electrophotochemistry was carried out in an operationally simple manner, setting the stage for challenging C−H trifluoromethylations of unactivated arenes and heteroarenes. The robust nature of the electrophotochemical manifold was reflected by a wide scope, including electron‐rich and electron‐deficient benzenes, as well as naturally occurring heteroarenes. Electrophotochemical C−H trifluoromethylation was further achieved in flow with a modular electro‐flow‐cell equipped with an in‐operando monitoring unit for on‐line flow‐NMR spectroscopy, providing support for the single electron transfer processes.

Highlights

Electrophotochemistry has enabled arene CÀH trifluoromethylation with the Langlois reagent CF3SO2Na under mild reaction conditions
Visible light photoredox catalysis has emerged as a transformative technique for molecular syntheses,[12] proving effective for single electron transfer cross-couplingtype reactions
With the optimized reaction conditions for the electrophotochemical CÀH trifluoromethylation in hand, we explored their versatility with a set of representative arenes 1 (Scheme 2)

Summary

Introduction

Electrophotochemistry has enabled arene CÀH trifluoromethylation with the Langlois reagent CF3SO2Na under mild reaction conditions. With the optimized reaction conditions for the electrophotochemical CÀH trifluoromethylation in hand, we explored their versatility with a set of representative arenes 1 (Scheme 2).

Results

Conclusion