Synthesis, structure, and thermolysis of pentacoordinate 1,3,2λ5-oxazaphosphetidines: the intermediates of aza-Wittig reactions

1,3,2λ5-Oxazaphosphetidines bearing the Martin ligand were synthesized by the reaction of the corresponding iminophosphorane and carbonyl compounds and characterized by X-ray crystallographic analysis. Thermolysis of the oxazaphosphetidine gave the cyclic phosphinate and the corresponding imine, indicating that the oxazaphosphetidine is an intermediate of the aza-Wittig reaction.