Indole synthesis: palladium-catalyzed C–H bond amination via reduction of nitroalkenes with carbon monoxide
作者:Tom H.H. Hsieh、Vy M. Dong
DOI:10.1016/j.tet.2008.11.034
日期:2009.4
nitroalkenes into indoles. Under mild reaction conditions (1 atm carbon monoxide, 110 °C), palladium catalyzes the reductive cyclization of nitroalkenes to form a putative nitrosoalkene intermediate, which then rearranges to provide 3-arylindoles in high yields. Notably, this novel C–H bond amination takes advantage of carbon monoxide as an inexpensive stoichiometric reductant and produces carbon dioxide as
硝基烯烃因其在众多合成转化中的多功能性而被称为“化学变色龙”。在此,我们描述了共轭硝基烯烃向吲哚的第一过渡金属催化的转化。在温和的反应条件下(1 atm一氧化碳,110°C),钯催化硝基链烯的还原环化反应,形成假定的亚硝基链烯中间体,然后将其重排以提供高收率的3-芳基吲哚。值得注意的是,这种新颖的C–H键胺化利用了一氧化碳作为廉价的化学计量还原剂,并产生了二氧化碳作为主要副产物。