A new route to enantiomerically pure 2,5-disubstituted pyrrolidines. Total synthesis of (+)-Pyrrolidine 197B.

Abstract

An enantioselective synthesis of(+)-pyrrolidine 197B, starting from the readily available lactol 1 is described. The key steps involve two chelation controlled additions of Grignard reagents to the carbonyl groups of lactols 1 and 5 and a highly stereoselective trans-pyrrolidine formation from the dimesylate 9. © 1994.