Recent Advances in Diphenylmethanone Oxime Reagent Chemistry for Unsaturated Bond Bifunctionalization via Energy Transfer Catalysis

The concurrent installation of C‐X (C, O, S, N) and C‐N bonds across unsaturated bond skeletons is an effective strategy for the preparation of ubiquitous motifs in pharmaceuticals and bioactive compounds. In recent years, the rapid development of bifunctionalization reactions has resulted in the emergence of bifunctional reagents as a research hotspot in this field. Among these, diphenylmethanone oxime reagents with highly active N‐O bonds featuring low dissociation energy have significantly advanced the research of bifunctionalization. These reagents possess special features to simultaneously form two chemical bonds or introduce two functional groups, which not only streamlines synthetic pathways but also enhances synthetic efficiency, displaying an excellent atom‐ and step‐economy. In addition, diphenylmethanone oxime reagents have been extensively employed in organic synthesis, attributed to their ability to facilitate the construction of complex organic structures and to provide innovative reaction pathways. In this review, we present a comprehensive overview of various diphenylmethanone oxime reagents and their applications in the bifunctional modification of unsaturated bonds through visible‐light‐mediated triplet–triplet energy transfer catalysis (TTEnT).