Stereoselective Preparation of (4S)-1-Methyl-4-Propyl-L-Proline Commencing from (cis)-4-Hydroxy-L-Proline

We present a recipe for the stereoselective conversion of commercial (cis)-4-hydroxy-L-proline into (4S)- 1-methyl-4-propyl-L-proline, an analogue of the amino acid fragment found in the clinically used antibacterial antibiotic lincomycin. Single crystal X-ray diffraction analysis of the final target’s hydrochloride salt confirms its identity and absolute stereochemistry.