Enantioselective synthesis of (R)-and (S)-N-Boc-morpholine-2-carboxylic acids by enzyme-catalyzed kinetic resolution : application to the synthesis of reboxetine analogs

The (R)- and (S)-N-Boc-morpholine-2-carboxylic acids 9 and 10 were prepared using an enantioselective synthesis employing a highly selective enzyme-catalyzed kinetic resolution of racemic n-butyl 4-benzylmorpholine-2-carboxylate (11) as the key step. Acids 9 and 10 were then converted efficiently and stereoselectively to reboxetine analogs 3 and 4.