反应详情

A solution of 33.6 g (3E,6R)-6,10-dimethyl-3,9-undecadien-2-one in one liter of ethyl acetate was hydrogenated over Raney-Nickel (2 g) during 21 hours (hydrogen uptake 10.7 l). Thereafter, the catalyst was filtered off and the filtrate was concentrated. According to gas chromatography the crude product (34) contained 77% (R)-6,10-dimethyl-2-undecanone. 15 g of the crude product (44% of the total amount) were chromatographed on silica gel (n-hexane/ethyl acetate). After distillation of the pure fractions there were obtained 8.1 g (R)-6,10-dimethyl-2-undecanone (99.8% purity according to gas chromatography). The enantiomeric purity was 96.6% ee, as determined by gas chromatographic diastereomer analysis of an acetal derivative with an optically active diol. This enantiomeric purity corresponds to that of the used starting material.

1. filtrationThereafter, the catalyst was filtered off
2. concentrationthe filtrate was concentrated
3. custom15 g of the crude product (44% of the total amount) were chromatographed on silica gel (n-hexane/ethyl acetate)
4. distillationAfter distillation of the pure fractions