Metal-assisted electrocyclic reaction in a CN–NC–CN system

Abstract

In a reaction with cis-Ru(phen)2Cl2, the 1:2 condensate of benzil dihydrazone and 2-formylpyridine or 2-acetylpyridine is found to undergo an electrocyclic rearrangement to yield the cation [Ru(phen)2{5,6-diphenyl-3-(pyridin-2-yl)-1,2,4-triazine}]2+, which has been isolated as its hexafluorophosphate salt and characterised by X-ray crystallography.