Phosphine-Mediated Photocatalytic Defluorinative Reductive Coupling of Alkynes and Trifluoromethyl Alkenes

Abstract The reductive coupling of alkynes and alkenes has emerged as a straightforward protocol for C–C bond formation from readily available feedstocks. Herein, we report a phosphine-mediated photocatalytic defluorinative reductive coupling of alkynes and trifluoromethyl alkenes with water as the hydrogen source, delivering a range of valuable gem-difluoroalkenes with excellent chemoselectivity under mild conditions. This strategy is gram-scale and can be applied for several pharmaceutical and natural product derivatives. Control experiments and spectroscopic analyses were conducted to probe the underpinning mechanism.