Insertion of Benzynes into the PN Bond of P-Alkenyl(alkynyl)-λ5-phosphazenes

Benzynes, generated from 2-(trimethylsilyl)phenyl triflates, have been found to react with P-Alkenyl-λ5-phosphazenes via a formal π-insertion into the PN bond. A subsequent retro [2 + 2] cycloaddition/6π electrocyclization/protonation cascade explains the formation of the resulting 1,4-benzazaphosphorinium triflates. P-Alkynyl λ5-phosphazenes and phosphane sulfides undergo similar transformations.