反应详情

To a cooled (0° C.) solution of 4,4-dimethylcyclohexanone (21 g, 0.17 mol) and dimethyl carbonate (45 g, 0.50 mol) in THF (400 mL) was added NaH (60% wt/wt in mineral oil, 17 g, 0.43 mol) portionwise over 30 minutes. The resulting slurry was allowed to stir at ambient temperature for 30 minutes followed by two hours at reflux. The reaction mixture was cooled (0° C.) and MeOH (30 mL) was added dropwise over 20 minutes. The resulting slurry was partitioned between 10% aqueous citric acid and ethyl acetate. The organic layer was washed with brine, dried over magnesium sulfate and concentrated in vacuo. Purification by vacuum distillation provided methyl 2-hydroxy-5,5-dimethylcyclohex-1-enecarboxylate (22.5 g, 75% yield). 1H NMR (400 MHz, CDCl3) δ 12.15 (s, 1H), 3.75 (s, 3H), 2.29 (t, 2H), 2.03 (s, 2H), 1.44 (t, 2H), 0.96 (s, 6H); MS (EI) for C10H16O3: 184 (M+).

1. waitfollowed by two hours
2. temperatureat reflux
3. additionwas added dropwise over 20 minutes
4. customThe resulting slurry was partitioned between 10% aqueous citric acid and ethyl acetate
5. washThe organic layer was washed with brine
6. dry with materialdried over magnesium sulfate
7. concentrationconcentrated in vacuo
8. customPurification
9. distillationby vacuum distillation