Asymmetric total synthesis of Tofacitinib

A novel stereoselective synthesis of Tofacitinib (CP-690,550), a Janus tyrosine kinase (JAK3) specific inhibitor, has been achieved starting from (5S)-5-hydroxypiperidin-2-one in 10 steps from 2 with a 9.5% overall yield. The potentiality of this synthetic route is the obtention of tert-butyl-(3S,4R)-3-hydroxy-4-methylpiperidine-1-carboxylate (6b) as a new chiral precursor involved in the synthesis of CP690,550, in a three-step reaction, without epimerizations, rather than the 5 or more steps used in described reactions to achieve this compound from analogues of 6b.