Base induced rearrangement of an α-bromophosphonamidate: stereochemistry of ring opening of the azaphosphiridine oxide intermediate as revealed by X-ray crystallography

Abstract

Methoxide-induced rearrangement of the α-bromophosphonamidate 1b(X = Br) gives two products, 2b and 3b, corresponding to breakdown of the intermediate azaphosphiridine oxide 4b by nucleophilic attack at phosphorus, and cleavage of the P–N bond (major pathway) with inversion of configuration or the P–C bond (minor pathway) with retention; this suggests involvement of a five-coordinate species as an intermediate, not merely as a transition state.