Harimoto Takashi, Tadokoro Tomoki, Sugiyama Soichiro, Suzuki Takanori, Ishigaki Yusuke
Department of Chemistry, Faculty of Science, Hokkaido University, N10 W8, North-ward, Sapporo, 060-0810, Japan.
Angew Chem Int Ed Engl. 2024 Jan 2;63(1):e202316753. doi: 10.1002/anie.202316753. Epub 2023 Nov 28.
The concept of a domino-type reaction has been applied in a wide range of fields such as synthetic organic chemistry, material engineering, and life science. To extend the domino concept to redox chemistry, we designed and synthesized a dimeric quinodimethane (QD) with a nonplanar dithiin spacer. The domino-redox properties can be activated by raising the temperature, based on a thermally equilibrated twisted conformation of QD, which has a higher HOMO level that is more readily oxidized. After one QD unit is oxidized (trigger), steric repulsion and electronic interaction between electrophores make the neighboring QD unit adopt a twisted conformation (domino process), which facilitates the following oxidation. Thus, a domino-redox reaction was achieved for the first time by a change in the HOMO level due to a drastic change in the molecular conformation.
多米诺骨牌型反应的概念已被应用于广泛的领域，如合成有机化学、材料工程和生命科学。为了将多米诺骨牌概念扩展到氧化还原化学领域，我们设计并合成了一种带有非平面二硫杂环戊二烯间隔基的二聚醌二甲烷（QD）。基于QD的热平衡扭曲构象，通过升高温度可以激活多米诺氧化还原性质，该构象具有更高的最高占据分子轨道（HOMO）能级，更容易被氧化。一个QD单元被氧化（触发）后，亲电试剂之间的空间排斥和电子相互作用使相邻的QD单元采用扭曲构象（多米诺过程），这有利于后续的氧化反应。因此，首次通过分子构象的剧烈变化导致的HOMO能级变化实现了多米诺氧化还原反应。
