反应详情

温度

-78 °C

A mixture of compound 3a (0.20 g, 0.78 mmol) as obtained in the above Example 3, n-Bu4NI (1.01 g, 2.73 mmol) and dry CH2Cl2 (5 mL) was stirred and cooled to −78° C. under nitrogen. Thereafter, a solution of BCl3 (1M, 2.73 mL, 2.73 mmol) in CH2Cl2 was added dropwise into the cold mixture. The resultant mixture was stirred and slowly warmed up to 0° C. over 2 hrs. After carefully quenching with ice water (10 mL), the mixture was stirred for a further 20 min, followed by neutralization with a saturated NaHCO3 solution (10 mL). After concentration in vacuo, the resultant residue was extracted with EtOAc (10 mL×5). The organic layers were combined and dried with anhydrous MgSO4. After filtration, the filtrate was concentrated in vacuo, followed by purification via silica gel column chromatography (ethyl acetate/n-hexane=1:3), thus giving the title compound 3b as a colorless crystal (0.18 g, 95% yield).

1. temperatureslowly warmed up to 0° C. over 2 hrs
2. customAfter carefully quenching with ice water (10 mL)
3. stirringthe mixture was stirred for a further 20 min
4. concentrationAfter concentration in vacuo
5. extractionthe resultant residue was extracted with EtOAc (10 mL×5)
6. dry with materialdried with anhydrous MgSO4
7. filtrationAfter filtration
8. concentrationthe filtrate was concentrated in vacuo
9. customfollowed by purification via silica gel column chromatography (ethyl acetate/n-hexane=1:3)