Sb‐to‐P Metathesis: A Direct Route to Structurally Constrained, Cationic P^III Compound

Abstract Structurally constrained, cationic P III compound [ LP ][ SbCl 4 ] with an OCO pincer‐type ligand ( L ) having a central carbene donor was directly synthesized via an Sb‐to‐P metathesis reaction between PCl 3 and LSb‐Cl . [ LP ][ SbCl 4 ] was isolated and its reactivity with small molecules (ROH and RNH 2 ) was studied, showing that [ SbCl 4 ] − is not an innocent counter anion, but an active participant in these reactions. When the [ SbCl 4 ] − was replaced with the [ CB 11 H 12 ] − ([ Cb ] − ) anion, the reactions were redirected to [ LP ] + cation only. The reactions with alcohols and amines led to the equilibrium between the products of the formal E−H (E=O, N) bond oxidative addition to the P‐center and products of the P‐center/ligand‐assisted bond activation. Remarkably, [ LP ] + activated the PhO−H and PhN(H)−H bonds in a reversible, thermoneutral fashion.