The synthesis of Ro-63-8695 can be performed by first coupling of D-proline-benzylester hydrochloride (I) with adipoyl chloride (II) by means of Et3N in dichloromethane to furnish benzyl 1-[6-[2(R)-carboxy-1-pyrrolidinyl]-6-oxohexanoyl]pyrrolidine-2(R)-carboxylate (III), which is finally hydrogenated over Pd/C in MeOH.