反应详情

Copper (II) bromide (63.4 g, 0.28 mol) was added to a stirred solution of the dione 2 (17.9 g, 0.14 mol) in methanol (280 ml) at room temperature, under an atmosphere of nitrogen. The reaction was heated under reflux for 90 minutes and then cooled to room temperature. The mixture was then filtered through celite, washing with dichloromethane (3×250 ml) and evaporated in vacuo. Flash chromatography (SiO2, 50% diethyl ether in hexane) gave the enedione 3 (11.3 g, 91.0 mmol, 64%) as a yellow oil; δH (300 MHz, CDCl3) 7.22 (2H, s, CH═CH), 1.17 (3H, s, CH3), 1.15 (3H, s, CH3); δC (75.5 MHz, CDCl3) 207.7 (s), 147.1 (d), 46.4 (s), 19.5 (q).

1. temperatureThe reaction was heated
2. temperatureunder reflux for 90 minutes
3. filtrationThe mixture was then filtered through celite
4. washwashing with dichloromethane (3×250 ml)
5. customevaporated in vacuo