反应详情

A solution of 3-chloro-5-methoxybenzaldehyde (22.8 g, 134 mmol; see step (i) above) in CH2Cl2 (250 mL) was cooled to 0° C. Boron tribromide (15.8 mL, 167 mmol) was added dropwise over 15 min. After stirring, the reaction-mixture for 2 h, H2O (50 mL) was added slowly. The solution was then extracted with Et2O (2×100 mL). The organic layers were combined, dried (Na2SO4), filtered and concentrated in vacuo. Flash chromatography on silica gel eluting with Hex:EtOAc (4:1) afforded the sub-title compound (5.2 g, 25%).

1. extractionThe solution was then extracted with Et2O (2×100 mL)
2. dry with materialdried (Na2SO4)
3. filtrationfiltered
4. concentrationconcentrated in vacuo