m-Chloroperbenzoic acid → (3S)-tert-butyl 3-((6S)-6-((2-methyloxiran-2-yl)methyl)-2-oxo-6-phenyl-1,3-oxazinan-3-yl)piperidine-1-carboxylate

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Reaction Steps

To a solution of (S)-tert-butyl 3-((R)-6-(2-methylallyl)-2-oxo-6-phenyl-1,3-oxazinan-3-yl)piperidine-1-carboxylate (2.98 g, 7.2 mmol) in dichloromethane (200 mL) was added m-CPBA (77% maximum, 3.3 g, 2 equiv). The mixture was stirred 3 h at rt before being diluted by dichloromethane (150 mL), washed by 5% NaOH solution (2×40 mL), 30% aq sodium thiosulfate solution (30 mL), satd aq NaHCO3 (30 mL), 30% aq sodium thiosulfate solution (30 mL), satd aq NaHCO3 (30 mL), brine (30 mL), and dried over Na2SO4. Filtration and concentration gave crude (3S)-tert-butyl 3-((6S)-6-((2-methyloxiran-2-yl)methyl)-2-oxo-6-phenyl-1,3-oxazinan-3-yl)piperidine-1-carboxylate (2.98 g 93% yield) which was used for next steps without further purification. LC-MS Method 1 tR=1.68 min., m/z 431 (M+1).

Provenance & Evidence