Photoredox catalyst-mediated direct regioselective phosphonylation of indoles

An efficient hetero-cross-dehydrogenative-coupling (hetero-CDC) reaction between N-protected indoles and phosphites to 2-indolyphosphites is described. The regioselective methodology took place in the presence of photo redox catalyst Ru(bpy)3(PF6)2 combined with oxygen as an clean oxidant when exposed to visible light, furnishing the 2-indolyphosphites as the exclusive products in moderate to good yields with good functional group tolerance. Moreover, the phosphonylation protocol was proved by the control reaction to proceed through the radical pathway.