Direct heteroarylation of 5-bromothiophen-2-ylpyridine and of 8-bromoquinolineviapalladium-catalysed C–H bond activation: simpler access to heteroarylated nitrogen-based derivatives

Abstract

The palladium-catalysed direct heteroarylation of the pyridyl-containing substrates, 2-(5-bromothiophen-2-yl)pyridine and 8-bromoquinoline, proceeds in moderate to high yields with a variety of heteroarenes in the presence of 1–2 mol% of a palladium catalyst. This approach allows the access to polyheteroaromatics which are interesting building blocks as (N⁁C)-chelate ligands. The reaction proceeds regioselectively at the C5 position of thiophenes, thiazoles, furans or pyrroles and tolerates various substituents such as formyl, acetyl, ester, nitrile or chloro on the heteroarene. Therefore, this method allows a straightforward modulation of the electron density distribution on such derivatives.