A new and general method for asymmetric synthesis of either enantiomer of 2-substituted pyrrolidines from a single starting material is described. Reductive cyclization of (SS)-γ- chloro-N-tert-butanesulfinyl ketimines with LiBHEt3 in THF at− 78 to 23° C afforded (SS, R)- N-tert-butanesulfinyl-2-substituted pyrrolidines in excellent yields (88− 98%) and with high diastereoselectivity (99: 1). The diastereoselectivity is controlled effectively by the choice ...
