Palladium-Catalyzed Synthesis of 4-Arylcoumarins Using Triarylbismuth Compounds as Atom-Efficient Multicoupling Organometallic Nucleophiles
作者:Maddali L. N. Rao、Varadhachari Venkatesh、Deepak N. Jadhav
DOI:10.1002/ejoc.201000134
日期:——
Triarylbismuth compounds have been cross-coupled as atom-efficientmulticoupling organometallic nucleophiles with 4-bromo- and 4-(trifluoromethylsulfonyloxy)coumarins underpalladiumcatalysis conditions. These reactions afforded an array of 4-arylcoumarins in high yields. The general palladium protocol has been demonstrated to be efficient for the coupling of both bromide and triflate derivatives
Cyclization of aryl 3-aryl propynoates into 4-arylcoumarins catalyzed by cyclometalated Platinum(II) complexes
作者:Olesia Zaitceva、Valérie Bénéteau、Dmitry S. Ryabukhin、Ivan I. Eliseev、Mikhal A. Kinzhalov、Benoit Louis、Aleksander V. Vasilyev、Patrick Pale
DOI:10.1016/j.tet.2020.131029
日期:2020.4
Cyclometalated (ppy)PtII complexes (ppy = 2-phenylpyridinato-C2,N) catalyze the intramolecular cyclization of aryl propynoates to form coumarins and benzocoumarins. The complex [(ppy)PtCl(MeCN)] (5 mol %) was the most active and efficient catalyst for such reaction, especially in the presence of AgSbF6 (15 mol %) in 1,2-dichloroethane. With this catalytic system, a wide range of substituents and functional