Substituent Effect on the Competition between Hetero??Diels??Alder and Cheletropic Additions of Sulfur Dioxide to 1??Substituted Buta??1, 3??dienes

…, F Monnat, P Vogel, K Schenk, P Roversi

Index: Roversi, Elena; Monnat, Frederic; Vogel, Pierre; Schenk, Kurt; Roversi, Pietro Helvetica Chimica Acta, 2002 , vol. 85, # 3 p. 733 - 760

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Citation Number: 26

Abstract

Abstract The reactivity of sulfur dioxide toward variously substituted butadienes was explored in an effort to define the factors affecting the competition between the hetero-Diels- Alder and cheletropic additions. At low temperature (<− 70), 1-alkyl-substituted 1, 3-dienes 1 that can adopt s-cis-conformations add to SO 2 in the hetero-Diels-Alder mode in the presence of CF 3 COOH as promoter. In the case of (E)-1-ethylidene-2- ...