Hydrazone-Initiated Reaction Cascades

摘要

In this Focus Review, recently reported cascade reactions that are initiated from hydrazones are described. These cascades are grouped based on the mechanistic characteristics of the reactions paired with the hydrazone-based transformations. Reactions in which the hydrazone simply acts as a surrogate for a diazo group are not discussed, but rather the focus is maintained on reactions with multiple mechanistically distinct steps. Sigmatropic, ene-yne metathesis, C-H bond insertion, ylide, and cross-coupling examples are given. The versatility of the hydrazone functional group allows for many transformations, and yet is also compatible with many other transformations. Finally, a discussion of potential future directions for hydrazone-initiated cascades is presented.