Photoinduced Phosphination of Arenes Enabled by an Electron Donor-Acceptor Complex Using Thianthrenium Salts.

Herein, we describe a metal-free approach for the cross-coupling of arenes or styryl-thianthrenium salts (TTs) with diarylphosphines via an electron donor-acceptor (EDA) complex. Various tertiary phosphines were obtained with high site selectivity and good functional group tolerance. This method enables straightforward construction of C-P bonds via C-H activation of arenes and allows the late-stage functionalization of natural products or pharmaceutical molecules. Mechanistic studies support the approach involving a photoinduced EDA complex.