Reactions of phosphines with acetylenes. Part XIII. Ring expansion of dibenzophosph(III)ole derivatives to give dihydrodibenzophosphorin oxides

Abstract

A series of dibenzophosphorin oxides has been prepared by ring expansion of dibenzophosph(III)oles with methyl propiolate. The structures of the oxides have been confirmed by independent synthesis. Ring expansion occurs to a considerable extent even when the phosphorus atom bears a benzyl group. The n.m.r. spectra of dibenzophosphorin oxides are discussed.