反应详情

(R)-2-Methyl-CBS-oxazaborolidine (1M in toluene, 1.95 ml, 1.95 mmol) was added to a flask containing 20 ml dry THF under Ar2(g) at 0° C. BH3.SMe2 (2M in THF, 6.0 ml, 12.0 mmol) was added over 5 min. 2-Bromo-1-(2,3-dihydro-benzo[1,4]dioxin-6-yl)-ethanone (4.7 g) was dissolved in 30 ml dry THF, added to a dropping funnel and added to the above solution slowly (ca 4 h) at 0° C. The mixture was stirred over night. The reaction was quenched by addition of 0.4 ml MeOH. The mixture was concentrated under reduced pressure, diethyl ether (200 ml) was added and the solution was extracted with 0.5M HCl (pH=1). The aq-phase was extracted with 100 ml diethyl ether and the combined organic phases were washed with ca 2% NaHCO3 followed by brine. The organic phase was dried with MgSO4 and concentrated to yield the title compound.

1. additionadded to a dropping funnel
2. additionadded to the above solution slowly (ca 4 h) at 0° C
3. customThe reaction was quenched by addition of 0.4 ml MeOH
4. concentrationThe mixture was concentrated under reduced pressure, diethyl ether (200 ml)
5. additionwas added
6. extractionthe solution was extracted with 0.5M HCl (pH=1)
7. extractionThe aq-phase was extracted with 100 ml diethyl ether
8. washthe combined organic phases were washed with ca 2% NaHCO3
9. dry with materialThe organic phase was dried with MgSO4
10. concentrationconcentrated