TMEDA-assisted effective direct ortho arylation of electron-deficient N-heteroarenes with aromatic Grignard reagents.

In the addition of TMEDA in toluene, aryl Grignards could effectively and site-specifically ortho-arylate electron-deficient heteroarenes under mild conditions. This endeavor successfully changed the old low-yielding reaction, aryl Grignard addition to N-heteroarenes, into an efficient procedure for heterobiaryls. The combination of the inexpensive aryl Grignards, TMEDA, the cost-free air, no use of any transition-metal catalyst, the mild reaction conditions, and the high-yielding gram-scale results enables this new procedure to be cost-effective and potentially utilizable in industry.