反应详情

A 70% solution of sodium bis (2-methoxyethoxy)-aluminum hydride in benzene (35 ml.) was stirred with ice bath cooling while a solution of 20.55 g. (0.0558 mole) of (S)-(-)-methyl-6-benzyloxy-2,5,7,8-tetramethyl- chroman-2-acetate in 50 ml. of benzene was added dropwise over 80 minutes keeping the temperature below 20° C. The resulting solution was stirred at room temperature for 2 hours then cautiously poured onto a mixture of ice and 1 N aqueous NaOH. Work-up by means of ether extraction in the manner of Example 1 afforded 19.8 g. of viscous colorless oil. This material was triturated with petroleum ether (30°-60° C.) and the resulting solid was filtered, washed with petroleum ether and dried under high vacuum giving 14.95 g. (78.7%) of (S)-(-)-6-benzylosy-2,5,7,8-tetramethyl-chroman-2-ethanol as a colorless solid, m.p. 55°-56° C.; [α]25D - 16.21° (c 2.03, CHCl3).

1. temperaturecooling while a solution of 20.55 g
2. customthe temperature below 20° C
3. extractionWork-up by means of ether extraction in the manner of Example 1
4. customafforded 19.8 g
5. customThis material was triturated with petroleum ether (30°-60° C.)
6. filtrationthe resulting solid was filtered
7. washwashed with petroleum ether
8. customdried under high vacuum
9. customgiving 14.95 g