Efficient asymmetric synthesis of optically pure tertiary mono and diphosphine ligands

The oxazaphopholidine borano complex 3, prepared in one step from ephedrine, reacts with alkyl and aryl lithium compounds to afford regio and stereoselectively the corresponding aminophosphine complexes 4. Acid methanolysis of 4 leads to the phosphinite borane complexes 5 which are used for the preparation of the mono and diphosphine boranes 6, 8, and subsequently the corresponding phosphines 7, 9 alter decomplexation with Et2NH. The preparation of (+) and (−)-PAMP 7a, DIPAMP 9a or β-BNPE 9b from the same complex 3 is described.