Hydrochloric Acid → Ethyl 2,2-dimethylpentanoate

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Reaction Steps

Under argon atmosphere, anhydrous THF (50 ml) and anhydrous diisopropylamine (8.8 mmol) were cooled with ice bath. After 10 minutes, n-butyl lithium (1.42N, 44.4 ml, 63 mmol) was added and the mixture was stirred for 30 minutes. Further, ethyl isobutyrate (7 ml, 52 mmol) dissolved in 15 ml anhydrous THF was added and the resulting mixture was stirred for 30 minutes. Then, HMPA (hexamethylphosphoric triamide: 3.3 ml, 20 mmol) was added to the reaction mixture and the mixture was stirred for 10 minutes. Propyl iodide (6.1 ml, 63 mmol) was also added and the mixture was stirred at room temperature for 30 minutes. Aqueous hydrogen chloride (6N) was added to the reaction mixture to adjust the pH to 7. After adding 100 ml of water, the mixture was extracted with ether (150 ml×3). The organic layers were washed with water (100 ml) and brine and dried over anhydrous sodium sulfate. After removal of ether and THF by distillation with Widmer column, the residue was distilled under reduced pressure to afford ethyl 2,2-dimethylpentanoate (3.81 g, 24.1 mmol, yield: 46%, b.p.=53° C./15 mmHg) as a colorless oil. The structure was identified by the following data.

Provenance & Evidence