1,2-Bis(2,5-diphenylphospholano)methane, a new ligand for asymmetric hydrogenation

1,2-Bis(2,5-diphenylphospholano)methane (Ph-BPM) has been prepared in good yield from 2,5-trans-diphenylphospholane–borane adduct. Rhodium and ruthenium complexes of this ligand have been prepared and their usefulness in asymmetric hydrogenation has been investigated. [Ph-BPM Rh(COD)]BF4 showed high activity and selectivity for itaconate and dehydroamino acid hydrogenation. Ph-BPM RuCl2(DPEN) was effective for imine hydrogenation.