(+/-)-Methyl 6-benzyloxy-2,5,7,8-tetramethylchroman-2-acetate → (6-Benzyloxy-2,5,7,8-tetramethylchroman-2-yl)acetaldehyde

Participants

Reaction Steps

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 addtional 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°.

Provenance & Evidence