Wavelength-tuned, photocatalytic chemoselective hydrodefluorination

Abstract

Selective hydrodefluorination of trifluoromethyl-bearing scaffolds remains challenging due to the unexpected over-defluorination. Herein, we report a photocatalytic chemoselective hydrodefluorination of trifluoromethyl acetamides enabled by readily tuning the wavelength of light irradiation, in which formate serves as both a hydrogen atom transfer (HAT) reagent and an electron donor for the EDA complex. This strategy enables the selective monohydrodefluorination and dihydrodefluorination of the trifluoromethyl unit under mild conditions, accommodating a variety of trifluoroacetamides. Mechanistic investigations disclosed that a wavelength-dependent SET/EDA manipulation is crucial to the chemoselectivity of this defluorination platform.