Ethyl isobutyrate → Ethyl 6-bromo-2,2-dimethylhexanoate

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Reaction Conditions

Reaction Steps

A solution of n-butyllithium (1.6M, 63 ml, 0.10 mol) in hexane was added dropwise to a solution of diisopropylamine (10.1 g, 0.10 mol) in anhydrous tetrahydrofuran (100 ml) at -50° C. The mixture was stirred for 0.5 hours. The mixture was cooled to -70° C. and a solution of ethyl isobutyrate (12.2 g, 0.105 mol) in tetrahydrofuran (20 ml) was added. The resulting mixture was stirred at -70° C. for 1 hour. 1,4-Dibromobutane (30.4 g, 0.14 mol) was added to the mixture followed by hexamethylphosphoramide (30 g). The resulting mixture was maintained at -70° C. for 0.5 hours and then warmed to room temperature over 1 hour. The solvent was evaporated off under reduced pressure and the residue was treated with saturated aqueous ammonium chloride (500 ml) and extracted with ethyl acetate (2×150 ml). The combined extracts were washed with water (100 ml), hydrochloric acid (1N, 2×100 ml) was saturated aqueous sodium hydrogen carbonate (100 ml) and dried over anhydrous magnesium sulfate. The solvent was evaporated off under reduced pressure and the residue was distilled to yield ethyl 2,2-dimethyl-6-bromohexanoate as a pale yellow oil, having a boiling point of 73° C., 0.06 mm.Hg and the following physical characteristics:

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