反応 #81151

反応方程式

1,1'-carbonyldiimidazole

magnesium chloride

mono-tert-butyl malonate

2,2-dimethyl-1,3-dioxolan-4-on-5-ylacetic acid

→

tert-butyl 4-(2,2-dimethyl-1,3-dioxolan-4-on-5-yl)-3-oxobutyrate

収率 77.2%

溶媒

tetrahydrofuran

dimethylformamide

triethylamine

tetrahydrofuran

反応条件

後処理

1. 1
   温度under cooling with ice
2. 2
   workup.STIRRINGThe mixture was stirred at room temperature for 3 hours
3. 3
   workup.ADDITIONAdded to this solution
4. 4
   その他separately prepared
5. 5
   workup.STIRRINGThe mixture was stirred at room temperature overnight
6. 6
   その他Insoluble matters were separated by filtration
7. 7
   その他Then, the filtrate was evaporated to dryness under reduced pressure
8. 8
   workup.DISSOLUTIONThe residue was dissolved in a liquid mixture of ethyl ether and water
9. 9
   workup.ADDITIONadjusted to pH 3 to 4 by an addition of 1N hydrochloric acid
10. 10
    その他The organic layer was collected by separation
11. 11
    洗浄washed with a saturated sodium chloride aqueous solution
12. 12
    乾燥dried over anhydrous magnesium sulfate
13. 13
    workup.DISTILLATIONThen, the solvent was distilled off under reduced pressure
14. 14
    workup.DISSOLUTIONThe residue was dissolved in ethyl acetate
15. 15
    その他was evaporated to dryness under reduced pressure

実験手順

132 g of mono-tert-butyl malonate was dissolved in 1.5 μl of tetrahydrofuran, and 49.2 g of magnesium chloride and 134 ml of triethylamine were added thereto with stirring under cooling with ice. The mixture was stirred at room temperature for 3 hours. Added to this solution was a liquid separately prepared by stirring 60.0 g of 2,2-dimethyl-1,3-dioxolan-4-on-5-ylacetic acid (Tetrahedron Letter, vol. 28, p. 1685 (1987)) in a liquid mixture of 500 ml of tetrahydrofuran and 100 ml of dimethylformamide together with 64.2 g of 1,1'-carbonyldiimidazole at room temperature for 2 hours. The mixture was stirred at room temperature overnight. Insoluble matters were separated by filtration. Then, the filtrate was evaporated to dryness under reduced pressure. The residue was dissolved in a liquid mixture of ethyl ether and water and then adjusted to pH 3 to 4 by an addition of 1N hydrochloric acid. The organic layer was collected by separation, then washed with a saturated sodium chloride aqueous solution and dried over anhydrous magnesium sulfate. Then, the solvent was distilled off under reduced pressure. The residue was dissolved in ethyl acetate and then passed through a column of 300 g of activated aluminum oxide. The solution passed through the column was evaporated to dryness under reduced pressure to obtain 72.4 g (yield: 77%) of tert-butyl 4-(2,2-dimethyl-1,3-dioxolan-4-on-5-yl)-3-oxobutyrate.

出典