Tetrahedron

Thermal electrocyclic ring-opening of cyclobutenes: stereoselective routes to functionalised conjugated (Z, E)-and (E, E)-2, 4-dienals

…, R Hayes, S Ingham, ST Saengchantara, RW Turner…

Index: Binns, Falmai; Hayes, Roy; Ingham, Stephen; Saengchantara, Suthiweth T.; Turner, Ralph W.; et al Tetrahedron, 1992 ,  vol. 48,  # 3  p. 515 - 530

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Citation Number: 50

Abstract

The cyclobutenecarbaldehyde 12 undergoes thermal electrocyclic ring-opening at low temperature, producing the (2Z, 4E)-hexadienal 13 exclusively. By contrast, unsymmetrical derivatives of cis-3-cyclobutene-1, 2-dicarboxylic acid undergo ring-opening at 80–110° C with low levels of stereoselectivity, which vary according to the balance of the electronic and, to a lesser extent, the steric nature of the substituents located on the rehybridising carbon ...