Base-Mediated Direct Arylation of Pyrrole Derivatives

Abstract

It appears that transition metal catalysts are not necessary to perform the direct arylation of electron-rich heterocycles with aryl iodides and bromides. Lithium tert-butoxide in DMF promotes this reaction for a variety of N-alkyl- and N-arylpyrroles as well as for benzofuran and some other electron-rich aromatic compounds and provides the desired products in moderate to high yields. In contrast to all previous reports on the Pd-catalyzed direct arylation of indolizine, the reaction mediated by lithium tert-butoxide proceeds selectively at position 5.

DOI: 10.1002/adsc.201000723