ASYMMETRIC-SYNTHESIS OF 3S,4R-DIHYDROXYPYRROLIDINES BY REGIOSELECTIVEAND STEREOSELECTIVE HYDROXYLATION OF 4-OXOPROLINE ENOLATE

A short, efficient and stereoselective synthesis of enantiomerically p ure (2R, 3S, 4R) 3,4-dihydroxy-2-hydroxymethylpyrrolidine, a galactosi dase inhibitor, from 4-hydroxy-L-proline is presented. The key steps a re the regio- and stereoselective hydroxylation of a 4-oxoproline enol ate and the stereoselective reduction of the resulting ketoalcohol. An N-(9-phenylfluoren-9-yl) moiety is used not only as an N-protecting g roup but as a regio- and stereochemical control element as well.