Institut für Organische und Biomolekulare Chemie, Georg-August University Göttingen, Tammannstr. 2, 37077 Göttingen, Germany.
Chemistry. 2011 Jul 18;17(30):8452-61. doi: 10.1002/chem.201003559. Epub 2011 Jun 10.
Molecular switches based on helical tetrasubstituted alkenes, substituted with either electron-withdrawing (CF(3), F, CN; 2a-c, 3a,c) or -donating substituents (Me, OMe; 2d,e), have been synthesized from acyclic precursors 4 and 5 in a domino carbopalladation/Stille reaction. This palladium-catalyzed process allowed the rapid assembly of two C-C bonds, two six-membered rings, and the tetrasubstituted double bond in a completely diastereoselective fashion. The electronic effects of the substituents on the overall switching process were investigated by alternating irradiation of two different wavelength regions. Although the substituents had only a small influence on the absorption maxima, drastic differences in the switching behavior were observed.
基于螺环四取代烯烃的分子开关，取代基为吸电子基团（CF(3)、F、CN；2a-c、3a,c）或供电子基团（Me、OMe；2d,e），已经通过非环前体 4 和 5 在一个串联碳钯化/Stille 反应中合成。这个钯催化的过程允许两个 C-C 键、两个六元环和四取代双键的快速立体选择性组装。通过交替辐照两个不同的波长区域，研究了取代基对整个开关过程的电子效应。尽管取代基对吸收最大值只有很小的影响，但观察到了开关行为的巨大差异。
