Visible-light-activated copper(I) catalyzed oxidative C-sp-C-sp cross-coupling reaction: efficient synthesis of unsymmetrical conjugated diynes without ligands and base

A novel visible-light-promoted copper-catalysed process for the C-sp-C-sp cross-coupling reaction of terminal alkynes at room temperature is described. The current photochemical method is simple, highly functional group compatible, and more viable towards the construction of bio-active 1,3-unsymmetrical conjugated diynes without the need of bases/ligands, additives and expensive palladium/gold catalysts.