Water → Cyclohexanone, 2-(2-propen-1-yl)-

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Reaction Steps

Into a 2 liter round bottom flask, equipped with Dean-Stark water separator, cyclohexanone (186 g, 1.90 moles, Aldrich) was dissolved in 1 liter toluene, and then pyrrolidine (292 g, 4.1 moles) was added. The mixture was brought to reflux overnight, during which 55 mL of water was collected. After switching to a distillation head, excess pyrrolindine and toluene were distilled off (1.2 liter). When most of the volatiles had been removed, aspirator vacuum was applied to assist in removal of residual toluene. In the same flask, the residue was dissolved in 1.2 liter of acetonitrile. Allyl bromide (305 g, 2.5 moles) was added dropwise. The mixture was heated slowly to gentle reflux overnight. After distilling off most of the acetonitrile and cooling, 1.2 liter of water was added and heated to reflux for 30 minutes. Extracted with ether after the mixture was cooled (200 mL×3). Combined ether layer was dried over sodium sulfate. The crude product, after removing the solvent, was purified by vacuum distillation: 73-78° C., 6.7 mmHg, Yield: 156 grams (59% for two steps). See also, Stork et al., J. American Chem. Soc., 85:207-222 (1963), and Johnson et al., J. American Chem. Soc., 88:149-159 (1966).

Provenance & Evidence