Collection of Czechoslovak Chemical Communications 

Abstract

While ferricyanide oxidation of achiral 4-(4-dimethylaminophenyl)-2,6-diphenyl-1-(pyridin-2-yl)pyridinium perchlorate (2) gave racemic 3-(4-dimethylaminophenyl)-1-phenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)prop-2-en-1-one (7), the same oxidative procedure applied to racemic 1-[5-(1-methylpyrrolidin-2-yl)pyridin-2-yl]-2,4,6-triphenylpyridinium perchlorate (5) or its dimethylamino derivative 6 let to mixtures of diastereoisomeric 3-[6-(1-methylpyrrolidin-2-yl)-2-phenylimidazo[1,2-a]pyridin-3-yl]-1,3-diphenyl-2-en-1-ones (8) or their dimethylamino derivatives 9, respectively.

Keywords: Ferricyanide oxidation; Sterically crowded heterocycles; Atropisomerism.