Facile chemoenzymatic enantioselective synthesis of (3S, 4S)-3-methoxy-4- methylaminopyrrolidine, a key intermediate for a new quinolone antitumor compound AG- 7352 has been described. This methodology illustrates the preparation of 3-azido-1- benzyloxycarbonyl-4-hydroxypyrrolidine starting from diallylamine via 1-benzyloxycarbonyl- 3-pyrroline obtained by ring-closing metathesis (RCM) employing Grubbs' catalyst. ...