Highly Regioselective Catalytic Oxidative Coupling Reactions: Synthetic and Mechanistic Investigations
摘要:
A highly efficient and regioselective Pd-catalyzed method for the oxidative coupling of arylpyridine derivatives is reported. Remarkably, the reactions proceed at room temperature and are compatible with diverse functionalities, including aryl halides and thiophenes. Mechanistic studies suggest that these transformations proceed via a previously unprecedented mechanism involving two different pyridine-directed C-H activation reactions-one at a PdII center and one at PdIV.
Highly Regioselective Catalytic Oxidative Coupling Reactions: Synthetic and Mechanistic Investigations
作者:Kami L. Hull、Erica L. Lanni、Melanie S. Sanford
DOI:10.1021/ja065718e
日期:2006.11.1
A highly efficient and regioselective Pd-catalyzed method for the oxidative coupling of arylpyridine derivatives is reported. Remarkably, the reactions proceed at room temperature and are compatible with diverse functionalities, including aryl halides and thiophenes. Mechanistic studies suggest that these transformations proceed via a previously unprecedented mechanism involving two different pyridine-directed C-H activation reactions-one at a PdII center and one at PdIV.
AbstractA 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.