反应详情

A solution of 10.6 ml of diisopropylamine in 75 ml of tetrahydrofuran was chilled to -70° C., and 46 ml of a 1.6N hexane solution of n-butyllithium were added dropwise to the solution. After completion of the addition, the mixture was stirred for 15 minutes, and a solution of 54.8 g of γ-butyrolactone in 50 ml of tetrahydrofuran was added dropwise over 55 minutes, and the mixture was stirred for 50 minutes. Further, a solution of 14.75 g of ethyl benzyloxyacetate in 50 ml of tetrahydrofuran was added, and the resultant mixture was stirred for 2.5 hours at -60 to -50° C. 5N hydrochloric acid was then added so as not to exceed 20° C. to adjust the pH of the mixture to 1-2. Ethyl acetate was added to the reaction system, and the resultant mixture was washed with a saturated saline solution. The organic layer was dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure. The thus-obtained crude product was subjected to column chromatography on silica gel (elution solvent: hexane:ethyl acetate=3:1→2:1→1:1) to obtain 13.01 g (yield: 87.2%) of the intended product as a colorless oil.

1. additionAfter completion of the addition
2. stirringthe mixture was stirred for 50 minutes
3. customto exceed 20° C.
4. washthe resultant mixture was washed with a saturated saline solution
5. dry with materialThe organic layer was dried over anhydrous sodium sulfate
6. distillationthe solvent was distilled off under reduced pressure
7. customThe thus-obtained crude product