反应详情

970 mg (3.23 mmol) of tert-butyl 4-bromo-3,5-dimethylphenylcarbamate (Example IV) are dissolved in 3 ml of cyclohexane and 3 ml of ether, cooled to −78° C., and added dropwise to 2.53 ml of 1.6 M methyllithium in ether at −78° C. After stirring at this temperature for 10 minutes, 3.8 ml of 1.7 M tert-butyllithium in pentane are added dropwise. The mixture is stirred at −78° C. for 1 hour and, after addition of 518 mg (2.9 mmol) of 3-isopropyl-4-methoxybenzaldehyde dissolved in 1 ml of ether/cyclohexane (1/1), stirred at −78° C. for 30 min and at room temperature for one hour. It is diluted with water and ether, the organic phase is washed with 10% strength citric acid solution, sodium bicarbonate solution and water and dried over sodium sulphate, and the solvent is removed in vacuo. Purification by chromatography (cyclohexane/ethyl acetate=9:1) affords 0.76 g (53%) of tert-butyl 4-[hydroxy(4-methoxy-3-isopropylphenyl)methyl]-3,5-dimethylphenylcarbamate.

1. stirringThe mixture is stirred at −78° C. for 1 hour
2. stirringstirred at −78° C. for 30 min and at room temperature for one hour
3. washthe organic phase is washed with 10% strength citric acid solution, sodium bicarbonate solution and water
4. dry with materialdried over sodium sulphate
5. customthe solvent is removed in vacuo
6. customPurification by chromatography (cyclohexane/ethyl acetate=9:1)