Synthesis of Unsymmetrical Bis(Phosphine) Monoxides and <i>N</i>‐Heterocyclic Carbene‐Phosphine Oxides through Michaelis–Arbuzov Reactions of Phosphinite Esters

A modular synthesis of bis(phosphine) monoxide (BPMO) ligands has been realized using the Michaelis–Arbuzov reaction of dialkylphosphinite esters. The modular synthetic method allows the chemoselective synthesis of BPMO ligands in which the substituents on the two phosphorus centers are different. This methodology also provides a route to N ‐heterocyclic carbene‐phosphine oxide ligand precursors.