Step 1: tert-Butyl ((3R,5R)-1-benzyl-5-methylpiperidin-3-yl)carbamate (0.6 g, 1.971 mmol, see WO2004014893 for preparation) was dissolved in ethanol (10 mL) and palladium carbon (Pd(OH)2/C, 0.1 g) was added. The reaction mixture was stirred at room temperature and under an atmosphere of hydrogen at 1 atm. After 2 h, the palladium catalyst was removed by filtration and the solvent was subsequently evaporated to afford 0.45 g of tert-butyl ((3R,5R)-5-methylpiperidin-3-yl)carbamate as a colorless oil in >95% yield.
[1] Patent: US2010/144745, 2010, A1. Location in patent: Page/Page column 44
[2] Patent: US2011/59118, 2011, A1. Location in patent: Page/Page column 53
[3] Journal of Medicinal Chemistry, 2011, vol. 54, # 6, p. 1871 - 1895