Computational Organic Chemistry : Examples of Applications

The interest of the organic chemists toward computational quantum mechanics (QM) is notably grown due to both the increasing performance of modern CPU’s and the software optimization for parallel applications. Indeed, quantum chemistry allows the prediction of several molecular properties (i.e. energy, favored geometry, spectroscopic properties) as well as the investigation of reaction mechanisms trough an accurate analysis of transition states (TS). In this manuscript we report two examples where quantum–chemical computational techniques were successfully applied to solve some questions raised within research projects in the field of organic chemistry. The first example concern the study of the tautomerism (a phenomenon of dynamic chemical equilibrium) of some imidazole derivatives, where their experimentally derived spectroscopic properties were compared with those theoretically computed for the single tautomers. In the second case, computational QM allowed the rationalization of the “double” reactivity of o-thioquinones toward Diels–Alder cycloadditions. The studies herein reported were performed thanks to the collaboration between the Università degli Studi di Milano and CILEA, which provided computational facilities