Photochemistry of 2,5-dialkyl-1,3,5-hexatrienes. The influence of the ground-state conformation, controlled through steric substituent effects
作者:A. M. Brouwer、L. Bezemer、J. Cornelisse、H. J. C. Jacobs
DOI:10.1002/recl.19871061203
日期:——
The photochemical reactions of a number of 2,5-dialkyl-1,3,5-hexatrienes are described. Variations in the selectivity of the reactions are observed, which can be rationalized by considering differences in the composition of the equilibrium mixture of conformational isomers, brought about by steric substituent effects. This result is in agreement with the NEER principle. In addition, examples are given
描述了许多2,5-二烷基-1,3,5-己三烯的光化学反应。观察到反应选择性的变化,这可以通过考虑由空间取代基效应引起的构象异构体的平衡混合物的组成差异来合理化。该结果与NEER原理一致。另外,给出了光诱导的异构化效率变化的实例,其不受NEER原理的限制。提出了一种涉及双自由基中间体的反应机理,该机理解释了所有包含三元环的反应产物的形成。MO相关图表明,作为主要步骤的三元环的形成必须以旋转方式发生。