The apicophilicity of the phenylseleno group in five-co-ordinate phosphoranes

Abstract

The variable-temperature n.m.r. spectra of spirophosphoranes containing a P-phenylseleno group show that in these systems phenylseleno, phenylthio, and phenoxy groups possess similar apicophilicities. In the case of a spirophosphorane containing a benzoxathiaphosphole ring there is no evidence for the presence in solution of an isomer with apical sulphur, i.e. there is here a substantial difference in apicophilicity between oxygen and sulphur which is not apparent with phenoxy and phenylthio groups.