反应详情

温度

-78 °C

The organoborane reagent 8 was prepared according to the procedure of Brown and Bhat5. To a stirred mixture of t-BuOK (1.15 g, 10.2 mmol) and trans-2-butene (4.0 mL, 44 mmol) in THF (8 mL) maintained at -78° C., was added BuLi (4.10 mL, 10.2 mmol, 2.5 M in hexanes). The mixture was then kept at -60° C. for 10 min and cooled to -93° C., at which time (+)-(E)-crotyldiisopinocampheylborane (8) (3.89 g, 12.3 mmol) in diethyl ether (14 mL) was added dropwise over a period of 18 min. The reaction mixture was stirred at -93° C. for 30 min, and boron trifluoride etherate (1.63 mL, 13.3 mmol) was then added dropwise over 3 min, followed by compound 7 (2.02 g, 6.43 mmol) in 1:1 Et2O-THF (20 mL) over a period of 12 min. The mixture was stirred at -93° C. for 30 min, then at -78° C. for 5 h. After this time sodium perborate17 (12.3 g, 79.9 mmol) and water (11 mL) were added, and the mixture was stirred for 10 h at room temperature. Brine (30 mL) was added, and the organic layer was separated. The aqueous layer was extracted with EtOAc (2×40 mL), and the combined organic layers were dried (MgSO4), concentrated, and submitted to silica gel chromatography (solvent A) to obtain 9 (1.58 g, 66%) as a syrup: [α]D20 +78° (c 1.0, acetone); 1H NMR (CDCl3): δ 0.93 (t, 3H, J=7.40 Hz, --CH2CH3), 0.96 (d, 3H, J=6.80 Hz, --CHCH3), 1.37, 1.43 (2s, 6H, --C(CH3)2), 1.51 (m, 2H, --CH2CH3), 2.56 (m, 1H, --CHCH3), 2.62-2.88 (m, 2H, --CH2CH2CH3), 4.57 (bs, 1H, --OH), 4.92-5.10 (m, 2H, --CH=CH2), 5.29 (d, 1H, J=7.0 Hz, --CHOH), 5.46 (d, 1H, J=10.0 Hz, H-3), 5.64 (s, 1H, H-9), 5.77-5.96 (m, 1H, --CH=CH2), 6.60 (d, 1H, J=10.0 Hz, H-4), 9.84 (s, 1H, Ar--OH); 13C NMR (CDCl3): δ 13.95, 16.38, 22.96, 27.35, 28.05, 38.48, 44.05, 72.60, 77.54, 102.71, 106.35, 107.09, 109.05, 116.27, 116.52, 126.66, 139.60, 151.00, 151.66, 156.03, 159.41, 161.67. Anal. Calcd for C22H26O5 : C, 71.33; H, 7.07. Found C, 70.46; H, 7.02. MS (negative-ion FAB): m/z 369 (M-1)-, 315.

1. additionwas added dropwise over a period of 18 min
2. stirringThe mixture was stirred at -93° C. for 30 min
3. waitat -78° C. for 5 h
4. stirringthe mixture was stirred for 10 h at room temperature
5. customthe organic layer was separated
6. extractionThe aqueous layer was extracted with EtOAc (2×40 mL)
7. dry with materialthe combined organic layers were dried (MgSO4)
8. concentrationconcentrated