Improved stereospecific synthesis of novel 1-alkyl-3-benzoyl-4-hydroxy-4-phenylpiperidines

The stereoselective synthesis of conformationally restricted 1-alkyl-3-benzoyl-4-hydroxy-4-phenylpiperidine hydrochlorides via the Mannich reaction followed by an intramolecular aldol condensation is reported. The compounds were evaluated by 1H NMR and 13C NMR techniques.