[3 + 2] Cycloaddition with photogenerated azomethine ylides in β-cyclodextrin
作者:Margareta Sohora、Leo Mandić、Nikola Basarić
DOI:10.3762/bjoc.16.110
日期:——
(AN) and 2@β-CD or 3@β-CD was also essayed by 1H NMR. Although the formation of such complexes was suggested, stability constants could not be determined. Irradiation of 2@β-CD in the presence of AN in aqueous solution where cycloadduct 7 was formed highly suggests that decarboxylation and [3 + 2] cycloaddition take place in the ternary complex, whereas such a reactivity from bulky adamantane 3 is less
通过1 H NMR滴定确定环己基邻苯二甲酰亚胺2和金刚烷基邻苯二甲酰亚胺3与β-环糊精(β-CD)的包合物的稳定性常数,分别为K = 190±50 M -1和K = 2600±600 M -1。研究了包合物2 @β-CD和3 @β-CD的光化学反应性,发现β-CD不会影响脱羧效率,但会影响后续的光化学H吸收,导致产物分布不同在β-CD存在下照射。与丙烯腈(AN)和三元配合物的形成还通过1 H NMR提出了2β-CD或3β -CD。尽管建议形成这种配合物,但无法确定稳定性常数。在形成环加合物7的水溶液中,在存在AN的情况下,对2β-CD的辐照高度表明在三元络合物中发生了脱羧和[3 + 2]环加成反应,而由大体积的金刚烷3发生这种反应的可能性较小。可以在β-CD腔中进行脱羧和环加成的这一原理证明对于设计用于控制光反应性的新超分子系统具有重要意义。
Photoinduced SET phthalimidation of unactivated double bonds and its application to the synthesis of protected phenethylamines
Phthalimide, in equilibrium with its conjugate base, adds photochemically to cyclohexene and aryl-substituted alkenes (photophthalimidation). The efficient, predictable regioselective photophthalimidation of styrenes constitutes a synthetically useful process for the preparation of N-phenethyl-phthalimides. A possible mechanism for the photophthalimidation involves the nucleophilic attack of phthalimide anion on the alkene cation-radical generated by single electron transfer to excited phthalimide. (C) 2003 Elsevier Science Ltd. All rights reserved.