Direct Synthesis of Heterobiaryls by Radical Addition to Pyridine: Expeditious Synthesis of Chelating Ligands

Abstract

The addition of aryl radicals to pyridine may be affected in moderate yield on exposure of aryl iodides to tributyltin hydride, AIBN, and diphenyl diselenide in hot pyridine. Mixtures of ortho-, meta-, and para-aryl substituted pyridines are typically obtained. When the iodide is ortho-substituted with a hydrogen bond donor, such as o-iodophenol, significantly improved selectivity for ortho-substituted pyridines, with potential as bidentate chelating ligands, is obtained.