Short asymmetric synthesis of (S,S)-PDP using l-prolinol derivative as economic starting material

(S,S)-PDP (5d) and its backbone (2S,2′S)-bipyrrolidine (1) have been extensively applied as the scaffold of various chiral ligands in catalytic asymmetric syntheses. In this study, new short asymmetric syntheses of these two important C₂-symmetrical nitrogen heterocycles have been accomplished employing economically available l-prolinol derivative 10 as the starting material. Excellent diastereoselectivity was achieved of the key Grignard addition to imine intermediate utilizing (S)-N-tert-butanesulfinamide as the chiral auxiliary.