反应详情

A solution of 31.17 g. of (±)-methyl 6-benzyloxy-2,5,7,8-tetramethylchroman-2-acetate in 3.11. of pentane was cooled under N2 to -70° Diisobutylaluminum hydride (24.4% in toluene; 87.3 ml.) in 87 ml. of pentane was added over 14 minutes. After 1.0 hour at -70°, another 8.73 ml. of diisobutylaluminum hydride was added and stirring was continued an additional 0.25 hour. The reaction was quenched by the careful addition of 250 ml. of methanol at -70°. The mixture was diluted with 1.01. of ether, washed with 0.5 N HCl, H2O, and brine and dried over sodium sulfate. Solvent removal gave a light yellow oil, which was filtered through 500 g. of silica gel with 90:10 benzene-ethyl acetate. Crystallization of the resulting oil from hexane - 30°-60° petroleum ether gave (±) 6-benzyloxy-2,5,7,8-tetramethylchroman-2-acetaldehyde as a white solid, m.p. 70°-75°.

1. waitwas continued an additional 0.25 hour
2. customThe reaction was quenched by the careful addition of 250 ml
3. customat -70°
4. additionThe mixture was diluted with 1.01
5. washof ether, washed with 0.5 N HCl, H2O, and brine
6. dry with materialdried over sodium sulfate
7. customSolvent removal
8. customgave a light yellow oil, which
9. filtrationwas filtered through 500 g
10. customCrystallization of the resulting oil from hexane - 30°-60° petroleum ether