The stereoselective synthesis of penmacric acid, an optically active C-4 substituted pyroglutamicacid, has been efficiently achieved through an unusual 11-step sequence starting from simple N-triisopropylsilylpyrrole. The key-steps are the initial addition of the pyrrole nucleus onto a chiral nitrone and the obtention of the pyroglutamicacid moiety by reductive hydrogenation of the pyrrole followed