反应详情

温度

-78 °C

To a stirring solution of 27 mL of DIBAL-H (1.5 M solution in toluene) in 10 mL of CH2Cl2 at −78° C. was added 1.32 g (7.54 mmol) of methyl 3-cyano-4-methylbenzoate in 35 mL of CH2Cl2 dropwise over a period of 30 min. After stirring for about 40 min. at −78° C., the solution was allowed to warm to r.t. After 75 min., the solution was cooled to −78° C. and 10 mL of H2O and 16 mL of 1N HCl were added. The cold bath was removed, and the mixture was allowed to warm to r.t. Concentrated HCl (5-6 mL) was added and stirring was continued for 1.5 h. Chloroform was added, the layers were separated, and the organic layer was washed with 20 mL of brine. The combined aqueous layers were extracted with chloroform (4×). The combined extracts were dried over Na2SO4, filtered, and concentrated. Purification by flash silica gel chromatography (50% EtOAc/hexanes) provided the 800 mg of 5-(hydroxymethyl)-2-methylbenzaldehyde as a yellow oil with some impurity.

1. temperatureto warm to r.t
2. waitAfter 75 min.
3. temperaturethe solution was cooled to −78° C.
4. customThe cold bath was removed
5. temperatureto warm to r.t
6. additionConcentrated HCl (5-6 mL) was added
7. stirringstirring
8. waitwas continued for 1.5 h
9. additionChloroform was added
10. customthe layers were separated
11. washthe organic layer was washed with 20 mL of brine
12. extractionThe combined aqueous layers were extracted with chloroform (4×)
13. dry with materialThe combined extracts were dried over Na2SO4
14. filtrationfiltered
15. concentrationconcentrated
16. customPurification by flash silica gel chromatography (50% EtOAc/hexanes)