(3R,4R)-1-Benzyl-N,4-dimethylpiperidin-3-amine

It provides the required (3R, 4R)-stereochemistry for the piperidine moiety, which is subsequently reacted with 4-chloro-7H-pyrrolo[3-d]pyrimidine, followed by debenzylation and acetylation to produce Tofacitinib citrate. (3R,4R)-1-Benzyl-N,4-dimethylpiperidin-3-amine is a critical chiral intermediate employed to synthesize the JAK inhibitor Tofacitinib (CP-690,550).