Substituent‐Controlled Reactions of Iminophosphoranes with Methyllithium

Totally different reactivity is observed in the reactions of the two isoelectronic iminophosphoranes Py3P  NSiMe3 (Py = 2-pyridyl) and Ph3P  NSiMe3 with methyllithium. While the first, even at −78 °C, spontaneously yields a monomeric amide on reduction of phosphorus(V) to phosphorus(III), the triphenyliminophosphorane yields the dimer 1 only after several days at room temperature in a deprotonation reaction of one phenyl ring in the ortho position.