反应详情

A solution of t-butyl (1R)-2-hydroxy-1-(4-(2-methylpentyloxy)phenyl)ethylcarbamate (500 mg, 1.48 mmol) prepared according to the procedure described in example 1, in dichloromethane (10 mL) was treated with sodium bicarbonate (622 mg, 7.41 mmol) and Dess-Martin Periodinane (1.26 g, 2.96 mmol) at room temperature. The mixture was stirred at room temperature under N2 for 1.5 h. The reaction mixture was placed in an ice-water bath and a 1:1 mixture of saturated aqueous NaHCO3 solution and saturated NaHSO3 solution (4 mL) was added and the cooling bath was removed and the mixture was stirred for 5 min at room temperature. The reaction mixture was transferred to a separatory funnel containing saturated aqueous NaHCO3 solution (20 mL). The aqueous layer was extracted with ethyl acetate (3×25 mL). The combined organic layers were washed with brine (20 mL), dried over MgSO4, filtered and concentrated. The residue was purified by column chromatography on silica gel (10%→15% ethyl acetate in hexanes, 25 g column) to afford t-butyl (1R)-1-(4-(2-methylpentyloxy)phenyl)-2-oxoethylcarbamate (318 mg, 64% yield) as a colorless oil which was stored in the freezer until used in the next step: 1H NMR (400 MHz, DMSO-d6) δ 9.48 (s, 1H), 7.76 (d, J=7.6 Hz, 1H), 7.23 (d, J=8.6 Hz, 2H), 6.93 (d, J=8.6 Hz, 2H), 5.11 (d, J=7.6 Hz, 1H), 3.82 (dd, J=9.6, 6.0 Hz, 1H), 3.73 (dd, J=9.3, 6.5 Hz, 1H), 1.82-1.92 (m, 1H), 1.40 (s, 9H), 1.25-1.49 (m, 3H), 1.11-1.22 (m, 1H), 0.96 (d, J=6.8 Hz, 3H), 0.88 (t, J=7.1 Hz, 3H); LRMS (ESI) m/e 279.2 [(M-t-Bu)+, calcd for C15H21NO4 279.1].

1. customThe reaction mixture was placed in an ice-water bath
2. additionwas added
3. customthe cooling bath was removed
4. stirringthe mixture was stirred for 5 min at room temperature
5. customThe reaction mixture was transferred to a separatory funnel
6. additioncontaining saturated aqueous NaHCO3 solution (20 mL)
7. extractionThe aqueous layer was extracted with ethyl acetate (3×25 mL)
8. washThe combined organic layers were washed with brine (20 mL)
9. dry with materialdried over MgSO4
10. filtrationfiltered
11. concentrationconcentrated
12. customThe residue was purified by column chromatography on silica gel (10%→15% ethyl acetate in hexanes, 25 g column)