反应详情

5.1 g (0.13 mol) of sodium borohydride, 700 ml of diglyme and 50.0 g (0.32 mol) of (-)-isopulegol were charged into a 1λ three-necked flask equipped with a condenser, a dropping funnel, a thermometer and a magnetic stirrer. 23.0 ml (0.13 mol) of boron trifluoride etherate was put in the flask on a water bath, and the contents thereof were agitated well for 15 min (precipitated). Further, the contents were agitated at room temperature for 1 hr, and then 50 ml of water was added to thereby decompose any excess hydroxide. 40 ml of a 3M aqueous sodium hydroxide solution was added to the organic borane formed by the above reaction on the water bath heated at 30° to 50° C. Further, 40 ml of a 30% aqueous hydrogen peroxide solution was added and agitated well for 30 mins. The reaction product was extracted with 1λ of ether and washed with the same amount of chilled water 5 times to thereby remove the diglyme. The resultant ether phase was dried over anhydrous magnesium sulfate, and the solvent was distilled off, thereby obtaining 45.0 g (yield: 80.8%) of (1R, 2S, 5R)-2-(2-hydroxy-1-methylethyl)-5-methylcyclohexanol in the form of white crystals (reference: Helv. Chim. Acta., 50(21), 153 (1967)).

1. customequipped with a condenser, a dropping funnel
2. custom(precipitated)
3. stirringFurther, the contents were agitated at room temperature for 1 hr
4. addition50 ml of water was added
5. addition40 ml of a 3M aqueous sodium hydroxide solution was added to the organic borane
6. customformed by the above reaction on the water bath
7. temperatureheated at 30° to 50° C
8. stirringagitated well for 30 mins
9. extractionThe reaction product was extracted with 1λ of ether
10. washwashed with the same amount of chilled water 5 times
11. customto thereby remove the diglyme
12. dry with materialThe resultant ether phase was dried over anhydrous magnesium sulfate
13. distillationthe solvent was distilled off