A conformationally constrained analogue 3 of the ACE inhibitor Idrapril has
been prepared by a five-step synthesis. The key step in the synthesis is t
he desymmetrization of endo-norborn-5-ene-2,3-dicarboxylic anhydride 4 by r
eaction with t-butyl (S)-prolinate. (C) 1998 Elsevier Science Ltd. All righ
ts reserved.