反应详情

Methyl isobutyryl acetate (7.20 g, 49.9 mmol) and sodium methoxide (0.896 g, 4.14 mmol) were cooled to 0° C. Methyl vinyl ketone (4.12 ml, 49.9 mmol) was added dropwise, and the solution was allowed to warm to rt and stirred 1 h at that temperature. Acetic acid (0.249 ml, 4.34 mmol) was added, followed by a mixture of MeOH (6.75 ml):Water (750 μL), and finally a solution of pyrrolidine (0.349 ml, 4.21 mmol) in acetic acid (0.309 ml, 5.39 mmol). The resultant solution was heated to reflux (115° C.) for 2 h. The reaction was allowed to cool to room temperature and then diluted with Et2O and water. The layers were separated and the aqueous portion extracted again with Et2O (1×). The combined organic layers were dried over Na2SO4 and concentrated in vacuo to afford methyl 4-oxo-2-(propan-2-yl)cyclohex-2-ene-1-carboxylate (5.11 g, 52%) as a yellow oil, which was used in the subsequent step without further purification.

1. temperatureto reflux (115° C.) for 2 h
2. temperatureto cool to room temperature
3. customThe layers were separated
4. extractionthe aqueous portion extracted again with Et2O (1×)
5. dry with materialThe combined organic layers were dried over Na2SO4
6. concentrationconcentrated in vacuo