Photo-Driven Difunctionalization of Unactivated Alkenes: Recent Advances in Radical-Mediated Strategies

The difunctionalization of alkenes serves as a powerful strategy for the simultaneous incorporation of two distinct functional groups across a carbon–carbon double bond, thereby enabling a rapid increase in molecular complexity. This transformation has found widespread application in modern organic synthesis due to its efficiency and versatility. In recent years, the advent of green and sustainable activation platforms, particularly using photochemistry, has significantly advanced this field. This mild and environmentally benign methodology has inspired innovative strategies for transforming abundant alkene and alkane feedstocks to complex scaffolds through radical pathways. In this review, we summarize recent progress in photo-driven alkene difunctionalization processes. Particular emphasis is placed on the unactivated alkenes, reaction design, and the mechanistic features of these transformations.