Photoredox and Copper Dual‐Catalyzed Cyclization of Alkyne‐tethered α‐Bromocarbonyls.

The synergistic systems of photoredox and copper catalyst have already appeared as a novel formation of green synthetic chemistry, which open new avenues for chemical synthesis applications. We describe a novel strategy for the cyclization of alkyne‐tethered α‐bromocarbonyls initiated by the cleavage of C(sp3)−Br bond via the collaboration of photoredox and copper catalyst. The present protocol exhibits mildness using economical copper catalyst and visible‐light at room temperature. The gram‐scale and sunlight irradiation experiments proceeded smoothly to show the practicality of the methodology. It is notable that the newly generated oxygen in the product originates from H2O. [ABSTRACT FROM AUTHOR]