Tetrahedron

Acid catalyzed ring closure reactions of electrophilic alkenes

…, N de Kimpe, D Courtheyn, L de Buyck, N Schamp

Index: Verhe, Roland; Kimpe, Norbert De; Courtheyn, Dirk; Buyck, Laurent De; Schamp, Niceas Tetrahedron, 1982 , vol. 38, # 24 p. 3649 - 3660

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Citation Number: 19

Abstract

Treatment of α-acyl-α, β-unsaturated ketones with sulfuric acid or dimethylformamide- hydrogen chloride or p-toluenesulfonic acid gave rise to 3-acyl-2-alkyl-4, 5-dihydrofurans. Similar cyclization of α-acyl-α, β-unsaturated esters initially afforded 3-alkoxycarbonyl-2- alkyl-4, 5-dihydrofurans which were transformed into 2-acylbutanolides on further reaction with sulfuric acid. This acid catalyzed cyclization is strongly dependent upon the ...