This review is based on the recent synthetic advancements of N‐tosylhydrazone under metal‐free conditions for the construction of nitrogen‐containing heterocycles. N‐Tosylhydrazones, an emerging building block in current organic chemistry offer moderate and flexible procedures through the carbene intermediates for the formation of C−C and carbon‐heteroatom bonds. N‐Tosylhydrazones are the derivatives of the aldehyde/keto group which act as carbene source, diazo precursors, and alternative of the respective carbonyl group. The key features of the N‐tosylhydrazone chemistry involve selective, controllable, one‐pot synthesis, good functional group tolerance, and metal‐free reactions with a wide scope of substrates. The current study includes mechanistic features, synthetic applications, substrate scope, limitation, and some additional reactions like electrosynthesis, regioselective, chemoselective, annulation, 1,3‐dipolar, and intermolecular cycloaddition.

This review highlights the advancement in the synthesis and applications of cyclic diaryliodonium salts as well as provides new areas for future research in this subject.