反应详情

温度

-78 °C

A solution of 5-(benzyloxy)-2,2-dimethyl-4H-benzo[d][1,3]dioxin-4-one (Example 38A, 4.00 g, 14.07 mmol) in dichloromethane (80 mL) was cooled to −78° C. and treated with a solution of diisobutylaluminum hydride (6.00 g, 42.2 mmol) in toluene (40 mL) added dropwise over 20 min. The resulting mixture was then stirred at −78° C. for 3 h. The reaction mixture was quenched by the careful addition of methanol (5 mL) added dropwise over 15 min, followed by 4 N hydrochloric acid (20 mL) added dropwise over 15 min. The cooling bath was then removed and an additional 80 mL of 4N hydrochloric acid was added over 10 min and the mixture was stirred vigorously at 22° C. for 4 h. The reaction mixture was diluted with ethyl acetate (200 mL), washed with brine, dried over anhydrous magnesium sulfate and evaporated in vacuo. The resulting oil was chromatographed on silica gel (4×10 cm, elution toluene) to give 2.25 g (70% yield) of the title material as a pale yellow solid. LC (Method A): 2.219 min. HRMS (ESI) calcd for C14H13O3 [M+H]+ m/z 229.0859. found 229.0859. 1H NMR (CDCl3, 600 MHz) δ ppm: 5.12 (s, 2H), 6.43 (d, J=8.25 Hz, 1H), 6.52 (d, J=8.46 Hz, 1H), 7.34-7.4 (m, 6H), 10.39 (s, 1H), 11.95 (s, 1H).

1. additionadded dropwise over 20 min
2. customThe reaction mixture was quenched by the careful addition of methanol (5 mL)
3. additionadded dropwise over 15 min
4. additionadded dropwise over 15 min
5. customThe cooling bath was then removed
6. additionan additional 80 mL of 4N hydrochloric acid was added over 10 min
7. stirringthe mixture was stirred vigorously at 22° C. for 4 h
8. additionThe reaction mixture was diluted with ethyl acetate (200 mL)
9. washwashed with brine
10. dry with materialdried over anhydrous magnesium sulfate
11. customevaporated in vacuo
12. customThe resulting oil was chromatographed on silica gel (4×10 cm, elution toluene)