Potassium t-butoxide alone can promote the biaryl coupling of electron-deficient nitrogen heterocycles and haloarenes

Org Lett. 2008 Oct 16;10(20):4673-6. doi: 10.1021/ol8019764. Epub 2008 Sep 25.

Abstract

The biaryl coupling of electron-deficient nitrogen heterocycles and haloarenes can be promoted by potassium t-butoxide alone, without the addition of any exogenous transition metal species. Electron-deficient nitrogen heterocycles such as pyridine, pyridazine, pyrimidine, pyrazine, and quinoxaline are arylated with haloarenes. Control experiments support a radical-based mechanism. Taking these findings into account, radical processes may be partially involved in the reported transition-metal-catalyzed arylation reactions employing t-butoxide bases and haloarenes under elevated temperatures or under microwave irradiation.