Hydrazone Phosphaketene as a Synthetic Platform To Obtain Three Classes of 1,2,4-Diazaphosphol Derivatives by Switchable Chemoselectivity Strategies

We introduce switchable chemoselectivity strategies based on the hydrazone phosphaketene intermediate to synthesize three classes of 1,2,4-diazaphosphol derivatives. First, the five-membered heterocyclic P and O anion intermediates acted as nucleophilic agents in the selective construction of C–P and C–O bonds. Second, the phosphinidene served as a phosphorus synthon, allowing for the formation of C–P and C–N bonds. Finally, a stepwise mechanism, supported by DFT calculations, was invoked to explain the reaction selectivity.