反应详情

243 g of alcohol 5 were dissolved in 1.56 L t-butyl methyl ether and charged into a 4-L three necked flask fitted with a reflux condenser and a thermometer. With stirring and cooling with an ice bath a mixture consisting of 155 g of sodium dichromate and 206 g sulfuric acid dissolved in 546 mL of water was added. The temperature was maintained below 20° C. during the addition. After the addition of chromic acid, the biphasic mixture was stirred for further 90 min at 25° C. until the TLC indicated complete consumption of the racemic alcohol 5. Then the aqueous layer was separated and 4× extracted with 390 mL of t-butyl methyl ether. The combined etheral solutions were successively washed with 624 mL of saturated sodium bicarbonate and sodium chloride solution, respectively. After drying with sodium sulfate and filtration the solvent was evaporated. Crystallization of the residual oil was induced by addition of a few crystals of authentic ketone 6 and about 25 mL of diethyl ether. To complete the crystallization 400 mL of n-hexane were added. An analytical sample was recrystallized from diethyl ether, mp: 48°-52° C., yield: 194 g (80%).

1. customfitted with a reflux condenser
2. temperaturecooling with an ice bath a mixture
3. additionwas added
4. temperatureThe temperature was maintained below 20° C. during the addition
5. stirringthe biphasic mixture was stirred for further 90 min at 25° C. until the TLC
6. customconsumption of the racemic alcohol 5
7. customThen the aqueous layer was separated
8. extraction4× extracted with 390 mL of t-butyl methyl ether
9. washThe combined etheral solutions were successively washed with 624 mL of saturated sodium bicarbonate and sodium chloride solution
10. dry with materialAfter drying with sodium sulfate and filtration the solvent
11. customwas evaporated
12. customCrystallization of the residual oil
13. additionwas induced by addition of a few crystals of authentic ketone 6 and about 25 mL of diethyl ether
14. customthe crystallization 400 mL of n-hexane
15. additionwere added
16. customAn analytical sample was recrystallized from diethyl ether, mp: 48°-52° C., yield: 194 g (80%)