Photoredox/palladium co-catalyzed propargylic benzylation with internal propargylic carbonates.

Herein, a highly regioselective propargylic benzylation with propargylic carbonates and benzyl 1,4-dihydropyridine derivatives was developed via a photoredox/palladium dual-catalyzed process, which represents a novel catalytic model for non-terminal propargylic functionalization. The reaction showed excellent regioselectivity and functional group compatibility. A radical coupling mechanism between the propargylic radical and benzyl radical was proposed.