反应详情

温度

0 °C

DIBAL-H (1.0 M in toluene) (33.8 mL, 33.8 mmol) was added dropwise to a solution of compound 227 (4.93 g, 16.9 mmol) in dichloromethane (85 mL) at −78° C. The reaction was stirred for 20 minutes, then warmed to 0° C. and quenched with 400 mL of 0.5 M Rochelle's salt saturated with NaCl. The mixture was stirred for 3 h then extracted with ethyl acetate (4×250 mL). The combined organics were washed with brine, dried over MgSO4, and concentrated in vacuo to provide 4.36 g of crude. The crude material was taken up in dichloromethane and methanol, plated onto silica gel, and flashed through a plug of silica using 30% ethyl acetate in hexanes, then switching to 10% methanol in DCM to provide compound 228 (3.37 g, 75.6% yield). 1H NMR (500 MHz, CDCl3) δ 8.60 (s, 1 H) 6.29 (s, 1 H) 4.83-4.95 (m, J=17.30, 8.59, 8.59 Hz, 1 H) 4.79 (d, J=5.87 Hz, 2 H) 2.62 (s, 3 H) 2.47-2.58 (m, 2 H) 1.97-2.15 (m, 5 H) 1.67-1.81 (m, 2 H) ppm.

1. customquenched with 400 mL of 0.5 M Rochelle's salt saturated with NaCl
2. stirringThe mixture was stirred for 3 h
3. extractionthen extracted with ethyl acetate (4×250 mL)
4. washThe combined organics were washed with brine
5. dry with materialdried over MgSO4
6. concentrationconcentrated in vacuo
7. customto provide 4.36 g of crude