Characterization of Enantiomeric Pairs of Optically Active 10-P-5 Phosphoranes with Asymmetry Only at Phosphorus

Diastereomeric phosphoranes (o-OC(CF3)2C6H4)2P*CH2CO2-(−)-menthyl (3-RP and 3-SP) of which absolute stereochemistry was determined were treated with LiAlH4 to give (o-OC(CF3)2C6H4)2P*CH2CH2OH (4-RP and 4-SP) as the first optically active pair of enantiomeric phosphoranes of rigid stereochemistry with asymmetry only upon the pentacoordinate phosphorus atom. The high enantiomeric purities of the alcohols were confirmed by converting them to their (+)-MTPA esters. Furthermore, when diastereomeric phosphoranes (o-OC(CF3)2C6H4)2P*CH2NHC*HCH3Ph (10-RP and 10-SP) of which absolute stereochemistry was also determined were treated with MeLi the first optically active pair of enantiomeric P–H phosphoranes (o-OC(CF3)2C6H4)2P*H (2-RP and 2-SP) with asymmetry only upon the pentacoordinate phosphorus atom could be obtained. The high enantiomeric purities of the P–H phosphoranes were confirmed by converting each of them to their corresponding (−)-menthyl esters 3-RP and 3-SP.