Photocatalyst‐free, Visible Light‐mediated Paternò‐Büchi Reaction Between Dicarbonyl Compounds and Olefines

Abstract The communication describes a general Paternò‐Büchi reaction under mild conditions, which is featured with visible light‐mediation, catalyst‐free and a broad range of substrates comparing with other strategies. Having overcome the synthetic limitations the PB reaction faces, this practical protocol can be employed to prepare a variety of multisubstituted oxetanes that often appear serving as important scaffolds in natural products and drugs. The common white light, the sole driving force in this case, can directly excite the carbonyl compounds to reach its triplet state, which then attacks an alkenes to generate a diradical intermediate, resulting in the oxetanes in high diastereoselectivity.