Recent advances in photoinitiated Pd-catalyzed desaturation and Heck-type reactions via 1,5-hydrogen atom transfer

Photoredox-catalyzed 1,5-hydrogen atom transfer has rapidly developed, which has made remarkable achievements in the activation of remote C(sp3)-H bonds and successfully addressed the selectivity issues faced by transition metal catalysis. In recent years, the discovery of hybrid Pd radical intermediates and their application in photoredox-catalyzed 1,5-hydrogen atom transfer has gained considerable importance, which obviated the necessity of an additional photosensitizer. In light of the significant role of alkenes in organic synthesis and hybrid Pd radical intermediates, this review aims to summarize efforts on photoinduced Pd-catalyzed radical relay Heck and desaturation reactions via 1,5-hydrogen atom transfer, briefly discussing the design, selectivity, reaction mechanisms and future research prospects.