Cross‐Dehydrogenative Homocoupling of 2‐Aryl‐N‐heterocycles and Application to the Synthesis of Phenylpyridine Borane Dimers

Abstract A method for the synthesis of 2‐aryl‐N‐heterocyclic dimers via a cross‐dehydrogenative homocoupling (homo‐CDC) has been developed using commercially available Ruthenium on charcoal as catalyst and iron trichloride as oxidant. A large variety of heterocyclic scaffolds and functional groups are tolerated and a complete regioselectivity resulting from the activation of the less sterically hindered C−H bonds was observed for meta ‐substituted substrates. Starting from several homocoupling products obtained, a series of pyridine‐borane complexes was synthesized and the impact of the dimerization on their photophysical properties was studied and rationalized using theoretical calculations.