反应详情

To a solution of (S)-3-((S)-1-(4-bromophenyl)ethyl)-6-(2-oxopropyl)-6-phenyl-1,3-oxazinan-2-one (20 g, 46.4 mmol) in anhydrous THF (200 mL) was added dropwise methylmagnesium bromide (31 mL, 144 mmol) at −78° C. under nitrogen. Then the mixture was stirred at rt for 1 h. The reaction mixture was quenched with aq NaHCO3 (50 mL) under ice water bath. The organic layers were separated. The aqueous layer was extracted with EtOAc (150 mL). The combined organic layers were washed with brine, dried over Na2SO4 and concentrated in vacuo to give the crude product, which was purified column chromatography (petroleum ether/EtOAc=5:1 to 2:1) to afford (S)-3-((S)-1-(4-bromophenyl)ethyl)-6-(2-hydroxy-2-methylpropyl)-6-phenyl-1,3-oxazinan-2-one (13 g, 65%). After re-crystallization from EtOH, 4 g of the pure compound was obtained. 1H NMR (CDCl3): 1.06 (s, 3H), 1.12 (s, 3H), 1.44 (d, 3H), 2.14 (m, 3H), 2.21 (m, 1H), 2.33 (m, 1H), 2.76 (m, 1H), 5.54 (q, 1H), 6.74 (d, 2H), 7.16 (d, 2H), 7.28 (m, 5H).

1. customThe reaction mixture was quenched with aq NaHCO3 (50 mL) under ice water bath
2. customThe organic layers were separated
3. extractionThe aqueous layer was extracted with EtOAc (150 mL)
4. washThe combined organic layers were washed with brine
5. dry with materialdried over Na2SO4
6. concentrationconcentrated in vacuo
7. customto give the crude product, which
8. customwas purified column chromatography (petroleum ether/EtOAc=5:1 to 2:1)