Enantioselective Synthesis of P-Chirogenic Phosphorus Compounds via the Ephedrine-Borane Complex Methodology

The stereoselective synthesis of P-chirogenic organophosphorus compounds using the versatile ephedrine-methodology is reported. The principle of the method is based on the diastereoselective preparation of 1,3,2-oxazaphospholidine borane 3 from ephedrine 2 and regio- and stereoselective ring-opening of the heterocycle leading to an aminophosphine borane 4. Finally, these ring-opening products 4 are easily transformed into P-chirogenic organophosphorus compounds, by subsequent highly stereoselective reactions involving electrophilic or nucleophilic strategies.