Heterogeneous visible-light promoted dehydrogenative [4 + 2] annulation of benzothioamides and alkynes under aerobic conditions
作者:Yanmin Guo、Rong Chang、Zhen Fu、Cong-Ying Zhou、Zhen Guo
DOI:10.1039/d3gc01329d
日期:——
The dehydrogenative [4 + 2] annulation is a step- and atom-economical way to construct benzo-fused six-membered rings which are prevalent in natural products, pharmaceuticals and agrochemicals. Herein, we disclosed a visible-light induced dehydrogenative [4 + 2] annulation of benzothioamides and alkynes, which was performed under mild aerobic conditions and catalyzed by the metal-free heterogeneous
脱氢[4 + 2]环化是构建苯并稠合六元环的一种步骤和原子经济的方法,苯并稠合六元环在天然产物、药物和农用化学品中普遍存在。在此,我们公开了苯并硫酰胺和炔烃的可见光诱导脱氢[4 + 2]成环反应,该反应在温和有氧条件下进行,并由无金属异质光催化剂石墨氮化碳(gC 3 N 4)催化。多相光催化操作简单、条件温和,进展顺利,并以良好的收率产生了多种异硫色烯。gC 3 N 4在光化学反应中表现出优异的稳定性和可回收性。详细的机制研究表明,gC3 N 4在可见光照射下通过单电子转移过程促进了以硫为中心的自由基的形成。自由基中间体进一步介导与炔烃的[4+2]环化,产生异硫色烯。