Collect. Czech. Chem. Commun.
2004, 69, 231-241
https://doi.org/10.1135/cccc20040231
Quantum-Chemical Insight Into Mechanism of Combined Intra-Intermolecular Cycloaddition
Petr Kulháneka,b, Milan Potáčekb and Jaroslav Kočaa,b,*
a National Centre for Biomolecular Research, Faculty of Science, Masaryk University Brno, Kotlářská 2, CZ-611 37 Brno, Czech Republic
b Department of Organic Chemistry, Faculty of Science, Masaryk University Brno, Kotlářská 2, CZ-611 37 Brno, Czech Republic
Abstract
Two different reaction mechanisms of a mixed criss-cross cycloaddition with opposite sequence of reaction steps, intra-intermolecular and inter-intramolecular, were explored by quantum-chemical calculations at the MP2 and B3LYP levels of theory and with cc-pVDZ basis set. It was found that the rate-determining step in the both mechanisms is the first step regardless of the mechanism. The Gibbs activation barrier of the intramolecular step of the intra-intermolecular sequence is by 10.4 kcal mol-1 lower than that of the intermolecular step of the inter-intramolecular sequence at the MP2 level of theory and almost the same at the B3LYP level of theory. This together with known experimental data confirms that the intra-intermolecular sequence is the most probable mechanism.
Keywords: Cris-cross cycloadditions; Density functional theory; Molecular modeling.
References: 16 live references.
