A Fast Track to Indoles and Annulated Indoles through ortho- vs ipso-Amination of Aryl Halides.Org Lett. 2019 12 20; 21(24):10143-10148.OL
A complementary site selective ortho- vs ipso-amination of aryl halides using non-electrophilic amine sources for construction of indole scaffolds is reported. A palladium-catalyzed alkyne insertion/C-H activation/palladacycle amination via merger of three easily diversified components including iodoarenes, alkynes, and amines delivers indoles with different substitution patterns even in gram scales. By employing ortho-bromoanilines, a consecutive annulative π-extension of indoles proceeds to construct indolo[1,2-f]phenanthridine scaffolds via four C-C and C-N bond formations in one pot.