“…Nitrile oxides participate in 1,3-dipolar cycloaddition with a range of alkynes, alkenes, and nitriles, following the reactivity order of C C > C C > C N. Takata first identified this reaction as a click system for the efficient, catalyst-free polymerization 74 of bis(nitrile oxide), and bisalkyne monomers leading to polyisoxazoles. 75,76 Nitrile oxides are highly reactive species that are often generated in situ from hydroxamoyl chloride and employed directly for sequential reactions 77,78 Takata explored kinetically stabilized aromatic nitrile oxides bearing two substituents at the ortho positions, which could be isolated. 79 Later, bulky aliphatic nitrile oxides that contain a fully substituted α-carbon were also investigated, and polymers with these moieties at the chain end have been prepared and shown to be stable.…”