191110-78-8

191111-27-0

The general procedure for the synthesis of methyl 1-((tert-butoxycarbonyl)amino)-4-hydroxycyclohexane-1-carboxylate from methyl 1-((tert-butoxycarbonyl)amino)-4-oxocyclohexanecarboxylate was as follows: tetrapropylammonium perruthenate (26 mg, 0.075 mmol) was added in a single step to stirred 1-((tert-butoxycarbonyl)amino)-4-hydroxycyclohexane-1-carboxylate methyl ester (410 mg, 1.5 mmol), N-methylmorpholine-N-oxide (264 mg, 2.25 mmol), and 4A molecular sieves (750 mg) in a mixture of 15 mL of 10% acetonitrile in dichloromethane solution. The reaction was carried out under argon protection. The reaction mixture was stirred for 1 h at room temperature and then the solvent was removed under reduced pressure. The resulting residue was purified by silica gel column chromatography (eluent: hexane solution of 30% ethyl acetate) to afford 372 mg (91.6% yield) of the target product methyl 1-((tert-butoxycarbonyl)amino)-4-oxocyclohexanecarboxylate as a white solid.1H NMR (CD3OD) δ: 1.43 [9H, s, -C(CH3)3], 2.32-2.42 (8H, m, 4×-CH2-), 3.74 (3H, s, COOCH3), 5.04 (1H, br, NH).