Synthesis of 5- and 6-Azaindoles by Sequential Site-Selective Palladium-Catalyzed C-C and C-N Coupling Reactions
Nguyen Thi Son, Tuan Anh Nguyen Tien, Marian Blanco Ponce, Peter Ehlers, Ngo Thi Thuan, Tuan Thanh Dang*, Peter Langer*
*Hanoi University of Science, Vietnam National University (VNU), Vietnam; University of Rostock, Albert-Einstein-Str. 29a, 18059 Rostock, Germany, Email: dangthanhtuanhus.edu.vn, peter.langeruni-rostock.de
N. T. Son, T. A. N. Tien, M. B. Ponce, P. Ehlers, N. T. Thuan, T. T. Dang, P. Langer, Synlett, 2020, 31, 1308-1312.
see article for more reactions
Site-selective Pd-catalyzed Sonogashira reactions of 3,4-dibromopyridine with alkynes, followed by Pd-catalyzed tandem C-N couplings and cyclizations with amines provide 6-azaindoles in very good yield. On the other hand, a 5-azaindole is obtained by a site-selective Pd-catalyzed C-N coupling reaction of 3,4-dibromopyridine with 4-toluidine, followed by C-C coupling and cyclization with phenylacetylene.
see article for more examples