Sodium hydride → (S)-tert-butyl 3-((R)-6-(2-methylallyl)-2-oxo-6-phenyl-1,3-oxazinan-3-yl)piperidine-1-carboxylate

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Reaction Steps

To a solution of (3S)-tert-butyl 3-((3-hydroxy-5-methyl-3-phenylhex-5-enyl)(methoxycarbonyl)amino)piperidine-1-carboxylate (5.80 g, 13 mmol) in dry THF (200 mL) was added NaH (60% in mineral oil, 1.04 g, 2 equiv). The mixture was heated to reflux for 2 h. After being cooled down to rt, the mixture was diluted with ether (200 mL), quenched with satd aq NH4Cl solution (25 mL), washed with 1% HCl solution (50 mL), brine (35 mL), and dried over Na2SO4. After filtration and concentration, the residue was purified by chromatography on a 120 g silica gel column, eluted with a 40-70% EtOAc in hexanes gradient to afford (5)-tert-butyl 3-((R)-6-(2-methylallyI)-2-oxo-6-phenyl-1,3-oxazinan-3-yl)piperidine-1-carboxylate (2.98 g, 55% yield). LC-MS Method 1 tR=1.92 min., m/z 437 (M+Na).

Provenance & Evidence