A Theoretical Study of Substituted Cyclobutanones and Their Enols

Abstract

MINDO-Forces calculations have been performed with complete optimization of the geometry on cyclobutanone and its enol counterpart, perfluorination of cyclobutanones and enol counterparts, and X-cycolobutanones and their X-enols, where X is NO 2 , CF 3 , CN, OH, NH 2 and F. It was found that ketone is more stable than its enol counterpart. Perfluorination destabilizes ketone on the expense of enol. These results agree with experimental and theoretical calculations. Electron releasing substituents (NH 2 , OH, F) stabilize cyclobutanone, while electron withdrawing substituents (CF 3 , NO 2 ) destabilize it. CN substituents have almost no effect on the stabilization of this keto-enol system.Geometrical parameters, heats of formation, electron densities and Gibbs free energy are reported.

Tautomeric Equilibria of Substituted 2-Pyridone/2-Hydroxypyridine in the Gas and Aqueous Phases

“…The stabilization effectwas also supported by isodesmic reactions [50][51][52][53][54][55][56]. A negative value for the reaction indicates a less stable, and a positive value indicates a more stable product.…”