Enantioselective synthesis of (2S,3S)- and (2R,3R)-pyrrolidine-2,3-dicarboxylic acids : conformationally constrained (S)- and (R)-aspartic acid analogues

Abstract The title compounds were prepared from the key intermediate 2 and its enantiomer at C2, derived from chiral synthons 1 - ( R ) and 1 - ( S ), respectively, by ethoxycarbonylation, desulfonylation and conversion to carboxylic acid.