A concise, stereoselective and scalable synthesis of optically pure (3R,4R)-1-benzyl- and (3R,4R)-1-Boc-3-methyl-4-aminopiperidines

An efficient, scalable and stereoselective synthesis of optically pure (3R,4R)-1-benzyl- and (3R,4R)-1-Boc-3-methyl-4-aminopiperidines has been developed starting from commercially available N-benzyl-3-methyl-4-piperidone. The synthesis employed chiral resolution of N-benzyl-3-methyl-4-piperidone, cis-selective reduction of a keto group, and subsequent Mitsunobu inversion of the resulting hydroxy group to install an amine with the desired trans-stereochemistry as the key steps. The method described herein demonstrated a competent route to the title compounds in a cost-effective, and scalable manner.