Unravelling nitrene chemistry from acyclic precursors: recent advances and challenges

Recent advances in nitrene chemistry from acyclic precursors are reviewed in this paper. Early developments in nitrene chemistry predominantly focused on exploiting new nitrene precursors and inventing new types of nitrene-based transformations. Organic azides, iminoiodinanes (even in situ generated iminoiodinanes), amines, and amide N-O compounds have all been reported as efficient acyclic nitrene precursors. Nitrene-based transformations mainly include C-H amination/amidation, aziridination, addition to unsaturated bonds, sulfimidation, etc. In many cases, asymmetric versions of C-H amination/amidation, aziridination and sulfimidation have been demonstrated. In this review, a particular emphasis is placed on reactions of nitrene with unsaturated bonds and reactions using amide N-O compounds as nitrene precursors. It can be seen that the reactivity of nitrene species can be controlled by the metal centre, ligand, type of nitrene precursor, and reaction system.