Applications of the ene reaction. Synthesis and properties of substituted α-methylene-γ-lactones

…, AW McCulloch, AG McInnes

Index: Hanson, Alfred W.; McCulloch, Archibald W.; McInnes, A. Gavin Canadian Journal of Chemistry, 1981 , vol. 59, p. 288 - 301

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Citation Number: 2

Abstract

Substituted dimethyl 1, 4-pentadiene-1, 2-dicarboxylates (1 or 3) may be prepared by AlCl3- promoted or thermal ene reaction of olefins with dimethyl acetylenedicarboxylate. Lactonization of these adducts is catalyzed by acid. In the presence of 80% H2SO4 the predominant product (ca. 80%) is a (Z)-dihydro-3-carbomethoxymethylene-2 (3 H)-furanone (2 or 4). Cyclization with anhydrous HCl affords a mixture of products, the composition of ...