反应详情

A solution of 11.3 g (40.0 mmol) dibenzylamino-acetic acid ethyl ester in 107 ml tetrahydrofuran and 107 ml toluene was stirred at −70° C. with 22 ml (44 mmol) lithium diisopropylamide (2M in heptane) for 30 minutes. 3.40 ml (46 mmol) acetone were added and stirring was continued overnight. The mixture was allowed to warm to room temprature, aqueous ammonium chloride solution was added. Extraction with diethylether and chromatography on silicagel with diethylether/heptane 1/2 yielded 7.16 g (52%) 2-dibenzylamino-3-hydroxy-3-methyl-butyric acid ethyl ester, MS m/e (%): 342.3 (M+H+, 100).

1. additionwas added
2. extractionExtraction with diethylether and chromatography on silicagel with diethylether/heptane 1/2