Theoretical investigation of the selectivity in intramolecular cyclizations of some 2'-aminochalcones to dihydroquinolin-8-ones and indolin-3-ones.

The selectivity of the intramolecular cyclizations of a series of 2'-aminochalcones was investigated with an approach that combines spin-polarized conceptual density functional theory and energy calculations. To that aim, condensed-to-atoms electrophilic Fukui functions, f NN (+) (r), were utilized as descriptors of the proclivity for nucleophilic attack of the NH2 group on the unsaturated α and β carbons. The results of our model are in excellent agreement with the experimental available evidence permitting us in all cases to predict when the cyclization processes led to the formation of 5-exo and 6-endo products.