反应详情

To a solution of NaNH2 (11.7 g, 91 mmol) in anhydrous ether (150 mL) under N2 at 30° C. was added dropwise a mixture of ethyl cyclobutanecarboxylate (19.2 g, 150 mmol) and acetone (21.75 g, 375 mmol). After addition, the reaction mixture was stirred for 4 h, then poured onto ice water with stirring. Ether was added and the unreacted components were extracted into the organic phase. The clear aqueous extract was acidified to pH 5.0 with 2 N HCl, and then to pH 7.5 with Na2CO3. The solution was extracted with ether. The combined organic layers were dried (Na2SO4), filtered, and concentrated to give the crude product of 1-cyclobutyl-1,3-butanedione (9.7 g, 76%), which was used in the next step without further purification. 1H NMR (400 MHz, CDCl3-d3) δ 5.42 (s, 1H), 3.66 (s, 1H), 2.11-2.23 (m, 4H), 2.02 (s, 3H), 1.93-1.99 (m, 2H).

1. additionAfter addition
2. additionpoured onto ice water
3. stirringwith stirring
4. extractionthe unreacted components were extracted into the organic phase
5. extractionThe clear aqueous extract
6. extractionThe solution was extracted with ether
7. dry with materialThe combined organic layers were dried (Na2SO4)
8. filtrationfiltered
9. concentrationconcentrated