A Novel N,P,C Cage Complex Formed by Rearrangement of a Tricyclic Phosphirane Complex: On the Importance of Non‐covalent Interactions

The reaction of Li/Cl P‐CPh₃ phosphinidenoid tungsten(0) complex 2 with dimethylcyanamide afforded tricyclic phosphirane complex 4 , an unprecedented rearrangement of which led to the novel N,P,C cage complex 6 . On the basis of DFT calculations, formation and intramolecular 3+2] cycloaddition of the transient nitrilium phosphane ylide complex 3 to a phenyl ring of the triphenylmethyl substituent to give 4 is proposed. Furthermore, theoretical evidence for terminal N‐amidinophosphinidene complex 7 , formed by 2+1] cycloelimination from 4 , is provided, and the role of the electronic structure and non‐covalent interactions of intermediate 7 discussed.