Recent Advances in Photoredox-Catalyzed Difunctionalization of Alkenes

Alkenes and their related analogs are ideal starting materials for organic synthesis, and the selective difunctionalization of alkenes, which allows the simultaneous introduction of two neighboring bonds, has gained considerable attention in recent years. In particular, the photoredox-catalyzed difunctionalization of alkenes has also been accomplished, which has been regarded as an increasingly powerful tool for the synthesis of miscellaneous interesting molecular scaffolds in an environmentally benign and economical manner. Several exquisite strategies have been developed to facilitate this transformation, such as photosensitizer-catalyzed redox reactions, electron donor-acceptor (EDA) complexes-mediated photoreactions, and atom transfer radical addition (ATRA) reactions. This literature review briefly describes the most recent key progress on the photoredox-catalyzed 1,2-difunctionalization of various structurally diverse alkenes, including 1,2-dicarbofunctionalization, 1,2-carboheterofunctionalization, and 1,2-diheterofunctionalization, with a special emphasis on the mechanistic details.