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

Participants

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 and cooled to -70° C. A solution of ethyl isobutyrate (12.2 g, 0.105 mol.) in tetrahydrofuran (20 ml) was then added and the resulting mixture was stirred at -70° C. for 1 hour. 1,4-Dibromobutane (30.4 g, 0.14 mol) was then added, followed by hexamethylphosphoramide (30 g). The 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, treated with an excess of an aqueous saturated solution of 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) aqueous saturated sodium hydrogen carbonate solution (100 ml) and dried (MgSO4). The solvent was evaporated off under reduced pressure and the residue was distilled to give ethyl 2,2-dimethyl-6-bromohexanoate as a pale yellow oil, (b.p. 73° C., 0.06 mm Hg).

Provenance & Evidence