反应详情

温度

90 °C

To a mixture of 1-chloro-2-methyl-4-nitro-5-isopropoxy-benzene (Intermediate 4, 870 mg, 3.77 mmol), vinylboronic acid dibutyl ester (1.24 mL, 5.6 mmol), and sodium carbonate (2.8 g, 26.4 mmol) in THF/H2O (20/5 mL) is added dichlorobis(triphenylphosphine) palladium (II) (132 mg, 5% mmol). The reaction tube is sealed, the mixture is purged with N2 for 3 min and then heated at 90° C. under N2 for overnight. The reaction is cooled to room temperature and poured into saturated aqueous ammonia chloride solution. The crude reaction mixture is extracted with ethyl acetate (3×100 mL). The organic extracts are combined, washed with brine and concentrated. The crude product is purified with silica gel column chromatography (10% ethyl acetate in hexanes) to afford 1-methyl-5-nitro-4-propoxy-2-vinyl-benzene as a yellow solid. 1-Methyl-5-nitro-4-propoxy-2-vinyl-benzene obtained from the previous step (360 mg, 1.63 mmol) is dissolved in DCM (20 mL) and is cooled to −78° C. O3 (g) is bubbled into the solution until the solution's color turns blue/gray. The solution is then purged with N2 (g) until the blue color disappears. The solution is warmed to room temperature and treated with triphenylphosphine resin (2 g) pre-swelled in DCM (30 mL). After 30 min, the mixture is filtered, and the filtrate is concentrated to afford 2-methyl-4-nitro-5-propoxy-benzaldehyde as yellow solid.

1. customThe reaction tube is sealed
2. customthe mixture is purged with N2 for 3 min
3. temperatureThe reaction is cooled to room temperature
4. additionpoured into saturated aqueous ammonia chloride solution
5. customThe crude reaction mixture
6. extractionis extracted with ethyl acetate (3×100 mL)
7. washwashed with brine
8. concentrationconcentrated
9. customThe crude product is purified with silica gel column chromatography (10% ethyl acetate in hexanes)