Intermolecular 1,2-Difunctionalization of Terminal Alkynes to Access Trisubstituted Alkenes via Copper/Photoredox Dual Catalysis.

We report a copper metallaphotocatalytic 1,2-difunctionalization of terminal alkynes with N -hydroxyphthalimide (NHP) esters and readily available silyl reagents (TMSCN and TMSNCS) to access stereodefined trisubstituted alkenes, including ( E )-alkenyl nitriles and thiocyanates. The reaction proceeds with excellent anti -stereoselectivity and demonstrates broad compatibility with a wide range of terminal alkynes and NHP esters as alkyl radical precursors. Experimental and computational studies have been performed to gain insight into the reaction mechanism.