Insights into the origin of high activity and stability of catalysts derived from bulky, electron-rich monophosphinobiaryl ligands in the Pd-catalyzed C-N bond formation

A relationship between the steady-state concentration of active Pd and the ligand size of monophosphinobiaryl ligands used in the amination of ary1 chlorides is demonstrated. The catalyst derived from the bulkiest ligand in the series, the tri-i-propyl ligand, exhibits both accelerated rate and the increased stability required for practical application of this reaction.