Polyene cyclization promoted by the cross-conjugated α-carbalkoxy enone system. Observation on a putative 1, 5-hydride/1, 3-alkyl shift under Lewis Acid catalysis

…, HM Wu, JD Wu, TW Ly, NW Jan, KS Shia, HJ Liu

Index: Chou, Ho-Hsuan; Wu, Huang-Min; Wu, Jen-Dar; Ly, Tai Wei; Jan, Ning-Wei; Shia, Kak-Shan; Liu, Hsing-Jang Organic Letters, 2008 , vol. 10, # 1 p. 121 - 123

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Citation Number: 17

Abstract

Polyene cyclization of compounds 3 and 4 under catalysis with AlCl3 and/or SnCl4 gave rise to complex bicyclic products 8 and 9, structures of which were highly unexpected, and X-ray analyses were invoked for unambiguously structural identification. Mechanistically, a tandem σ-bond rearrangement process, including an unusual through-space 1, 5-hydride or 1, 3-alkyl shift as a key operation, is proposed.