反应详情

DIBAL-H (8.66 mL, 12.99 mmol) was added dropwise to a solution of methyl 2-(4-bromo-2,6-dimethylphenyl)acetate (3.18 g, 12.37 mmol) in CH2Cl2 (60 mL) at −78° C. and stirred for 1 h. 1-(tert-Butyldimethylsilyloxy)-1-methoxyethene (4.05 mL, 18.55 mmol) followed by BF3.OEt2 (1.959 mL, 15.46 mmol) were added. The reaction was stirred at −78° C. for 20 min and then allowed to warm to rt. The reaction was quenched by the addition of 10 mL of 1.0 M HCl, extracted with dichloromethane. The combined organics were washed with brine, dried over Na2SO4 and concentrated in vacuo. The crude product was purified by flash chromatography (loading in chloroform, 0% to 50% ethyl acetate in hexane over 15 min using a 40 g silica gel cartridge) to yield 2A (2.5 g, 8.30 mmol, 67.1% yield) as a clear oil. 1H NMR (500 MHz, chloroform-d) δ ppm 7.18 (2H, s), 4.20-4.28 (1H, m), 3.72 (3H, s), 2.91 (1H, dd, J=14.03, 8.25 Hz), 2.72-2.78 (2H, m), 2.53-2.57 (2H, m), 2.55 (2H, dd, J=40.03, 6.19 Hz), 2.33 (6H, s), 1.58 (2H, br. s.).

1. additionwere added
2. stirringThe reaction was stirred at −78° C. for 20 min
3. customThe reaction was quenched by the addition of 10 mL of 1.0 M HCl
4. extractionextracted with dichloromethane
5. washThe combined organics were washed with brine
6. dry with materialdried over Na2SO4
7. concentrationconcentrated in vacuo
8. customThe crude product was purified by flash chromatography (loading in chloroform
9. wait0% to 50% ethyl acetate in hexane over 15 min using