Ammonium Chloride → 2-(1-Cyclopropyl-1-methylethyl)malonic acid diethyl ester

Participants

Reaction Steps

Step A To a suspension of CuI (7.61 g, 40 mmol) in anhydrous tetrahydrofuran (100 mL) at −50° C. was added cyclopropylmagnesium bromide (0.5 M, 160 mL, 80 mmol) during a period of 15 min. After the addition was finished, the reaction mixture was gradually warmed room temperature and stirred for 20 min. Then the temperature of the mixture was lowered to −50° C., a tetrahydrofuran solution (50 mL) of diethyl isopropylidenemalonate (Aldrich) (4 g, 20 mmol) was added. The reaction mixture was allowed to slowly warmed to room temperature and stirred for 3 h. Aqueous saturated NH4Cl solution was added to quench the reaction. The mixture was filtered, and the filtrate was concentrated to remove most of tetrahydrofuran. The residue was extracted with ethyl acetate twice. The organic layers were combined, concentrated. The residue was purified by chromatography (EtOAc:hexanes=1:20, 1:10) to give 2-(1-cyclopropyl-1-methyl-ethyl)-malonic acid diethyl ester as a colorless oil (4.3 g, 89%).

Provenance & Evidence