Comments on the electronic structure and reactivity of chromones

Abstract

AB initio calculations of ground-state wavefunctions of chromones and thiochromones have been carried out and correlated with the observed reactivity of these molecules. Quantum mechanical electrostatic potentials correctly predict nucleophilic attack to occur preferentially at C-2 and C-4 in chromones and thiochromones respectively. Frontier-orbital considerations correctly predict the site selectivity of the photochemical cycloaddition to the pyrone double bond of chromone.