反应详情

温度

-78 °C

To a solution of 2-bromo-3-(4-methoxy-butyl)-cyclohex-2-enone (2) (32.0 g, 123 mmol) in dry toluene (480 mL) at −95° C. was added (S)-methyl-oxazaborolidi-none (for making isomer 3) or(R)-methyl-oxazaborolidinone (for making isomer 3″) (1 M solution in toluene; 25 mL, 25 mmol). Catecholborane (1 M solution in toluene; 160 mL, 160 mmol) was added dropwise at −95° C. over a period of 10 hours and the reaction mixture stirred at −78° C. overnight. A 1 M NaOH solution (500 mL) was added and the temperature allowed to rise to room temperature. The organic layer was separated and the aqueous layer extracted with Et2O. The combined organic layers were washed with a 1 M NaOH solution and dried over anhydrous MgSO4. The solvent was removed in vacuo, and the resulting residue purified over silica (isooctane/EtOAc, 8:2) to afford 31.5 g (97% yield) of the desired product as a colorless oil which was characterized as follows:

1. customto rise to room temperature
2. customThe organic layer was separated
3. extractionthe aqueous layer extracted with Et2O
4. washThe combined organic layers were washed with a 1 M NaOH solution
5. dry with materialdried over anhydrous MgSO4
6. customThe solvent was removed in vacuo
7. customthe resulting residue purified over silica (isooctane/EtOAc, 8:2)