Co(II)‐Catalyzed Oxidation of N,N‐Dimethylaminoethanol: An Efficient Synthesis of Unsymmetrical (2,4‐) and Symmetrical (2,6‐) Diarylpyridines through Annulation of Aromatic Ketones with a Nitrogen Source

Abstract

AbstractAn efficient and facile synthesis of 2,4‐ and 2,6‐diarylpyridines has been developed. It involves one‐pot [2+2+1+1] pseudo four‐component annulation of aromatic ketones, a nitrogen source and a carbon donor. N,N‐Dimethylaminoethanol is oxidized in the presence of Co(II) to provide a carbon synthon. Two C−C and two C−N bonds are formed during the oxidative annulation process. The products are strictly controlled due to the steric hindrance: 2,4‐diarylpyridines are afforded effectively with small ketones while 2,6‐diaryl analogues predominate when bulky ketones are employed.