A Transient Vinylphosphinidene via a Phosphirene–Phosphinidene Rearrangement

A room-temperature-stable crystalline 2H-phosphirene (1) was prepared by treatment of an electrophilic diamidocarbene with tert-butylphosphaalkyne. Compound 1 is shown to react as a vinylphosphinidene generated via phosphirene–phosphinidene rearrangement. Thermolysis is shown to affect C–N bond scission while reactions with C6Cl4O2 or (tht)­AuCl afford formal oxidation of the phosphindene center and the phosphinidene-insertion into an aromatic C–C bond of a mesityl group, respectively. The latter reaction is the first example of a phosphorus analog of the Büchner ring expansion reaction.