Potassium Hydroxide → Diisopropyl 2-vinylcyclopropane-1,1-dicarboxylate

Beteiligte Stoffe

Reaktionsschritte

To illustrate the preparation of vinylcyclopropane derivatives via malonic ester condensation in an aqueous medium, the following experiment was conducted: To a flask provided with a stirrer and containing 125 g (1.0 mol) trans 1,4-dichlorobutene-2, 94 g (0.50 mol) diisopropyl malonate and 3.2 g (1.63 mol percent based on the malonate ester) tricaprylylmethylammonium chloride were added dropwise over a 30-minute perid with vigorous stirring 168 g 50% aqueous potassium hydroxide solution. Cooling was provided to maintain the reaction temperature at 25°-30° C. After five hours the reaction mixture was poured into water and extracted three times with ethyl ether. The combined etheral layers were dried over magnesium sulfate, filtered and concentrated to afford 184 g (67.2% yield) diisopropyl 2-vinylcyclopropane-1,1-dicarboxylate. Bp 77°-78° C.(0.5 mm); nD24° 1.4482. Infrared and proton nmr spectra were consistent with the desired structure. Similar results were obtained using other quaternary ammonium compounds, however, when the onium compound was omitted the reaction did not proceed.

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