Dicyclopropyl ketone → 4-Carbethoxy-5-phenyl-2-vinyl-2,3-dihydrofuran

Beteiligte Stoffe

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4-Carbethoxy-5-phenyl-2-vinyl-2,3-dihydrofuran was obtained in the usual manner by isomerizing ethyl 1-benzoyl-2-vinylcyclopropane-1-carboxylate. To catalyze the isomerization, tricaprylylmethylammonium chloride was employed at a 20 percent weight level. The mixture was heated at 150° C. for about two hours after which time only about 7 percent of the cyclopropyl ketone remained. After two distillations, essentially pure 4-carbethoxy-5-phenyl-2-vinyl-2,3-dihydrofuran was obtained. The product (B.P. 110° C. @ 0.1 mm Hg: nD25° 1.5570) had a pleasing aroma that was somewhat coumarin-like in odor character. Nuclear magnetic resonance and infrared spectroscopic analysis confirmed the structure ##STR16##

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