Reactions of ethoxyethynylphosphines with phenyl azide and nucleophiles. 1,5-Alkylotropic migration in phosphorus(IV)-substituted ketene acetals

Ethoxyethynyl-di-tert-butylphosphine reacts with phenyl azide in the presence of amines, alcohols, phenol, or water by addition of the nucleophile to the triple bond of the unstable ethoxyethynyldi-tert-butyl-N-phenyliminophosphorane. It has been found that iminophosphorylated ketene acetals are usually unstable, undergoing 1,5-alkylotropic migration to give alkoxycarbonylmethyl-ene(alkylphenylamino)phosphoranes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2850–2855, December, 1991.