Shi Yong-Gang, Mellerup Soren K, Yuan Kang, Hu Guo-Fei, Sauriol Francoise, Peng Tai, Wang Nan, Chen Pangkuan, Wang Suning
Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials , School of Chemistry , Beijing Institute of Technology , Beijing 100081 , P. R. China.
Department of Chemistry , Queen's University , Kingston , Ontario K7L 3N6 , Canada . Email:
Chem Sci. 2018 Mar 27;9(15):3844-3855. doi: 10.1039/c8sc00560e. eCollection 2018 Apr 21.
The key intermediate, 4a,4b-dihydrophenanthrene (DPH), involved in the photocyclization of stilbene and derivatives is known to be unstable, and is therefore poorly characterized/understood. We have found that functionalising stilbenes with NMe and BMes groups can greatly enhance the stability of 4a,4b-DPHs, allowing quantitative isolation and full characterization of these rare species. Furthermore, we discovered that the new amino-borane decorated 4a,4b-DPHs can undergo thermal [1,5] H sigmatropic shift, forming isomers 4a,10a-DPHs. Both 4a,4b-DHPs and 4a,10a-DHPs are stable towards air and moisture, while only the former were found to undergo oxidative dehydrogenation upon irradiation at 365 nm under air, yielding brightly blue/green fluorescent NMe and BMes functionalised phenanthrene analogues. Control studies established that the -MesB-Ph-NMe unit is responsible for the stability of these isolated 4a,4b-DHPs and their [1,5]-H shift isomers.
已知参与芪及其衍生物光环化反应的关键中间体4a,4b-二氢菲（DPH）不稳定，因此其特性了解甚少。我们发现，用NMe和BMes基团对芪进行官能化可以大大提高4a,4b-DPHs的稳定性，从而能够对这些稀有物种进行定量分离和全面表征。此外，我们发现新的氨基硼烷修饰的4a,4b-DPHs可以发生热[1,5]H 迁移反应，形成异构体4a,10a-DPHs。4a,4b-DHPs和4a,10a-DHPs对空气和水分都很稳定，而在空气中365nm光照下，只有前者会发生氧化脱氢反应，生成亮蓝色/绿色荧光的NMe和BMes官能化菲类似物。对照研究表明，-MesB-Ph-NMe单元是这些分离得到的4a,4b-DHPs及其[1,5]-H迁移异构体稳定性的原因。
