Palladium-catalyzed intramolecular arylation of electron-poor heterocycles

Formation of aryl-aryl bonds is a very interesting reaction especially for the synthesis of new chemical entities in drug discovery[1]. One of the most utilized method is the metal-catalyzed cross-coupling reaction with the limitation of the use of activating group in both of the arene coupling partner. Recently palladium-catalyzed direct arylations have emerged as attracting alternative. The advantage of this reaction consist in the opportunity to start from very simple building blocks: a non-activated aryl C-H bond and an aryl-halide. Most literature citation involves electron rich substrate[2], on the contrary there are only few examples regarding electron-poor heterocycles[3]; we report intramolecular version of this reaction regarding azines and diazines. Starting from functionalized nicotinic amides and 1,2-, 1,3- and 1,4-diazine amides, in only one step, azapolycyclic systems are obtained