Resumo

RUBIO, Manuel Fernando; JIMENEZ-CRUZ, Federico  e  RAMIREZ-GALICIA, Guillermo. Theoretical Study of the Electronic Effects in the Intramolecular Ketene-Styrene [2+2] Cycloaddition. J. Mex. Chem. Soc [online]. 2010, vol.54, n.4, pp.209-215. ISSN 1870-249X.

DFT (B3LYP/6-31+G*) and post-Hartree-Fock (MP2/6-31+G*//B3LYP/6-31G*) calculations were carried out in order to explain the effect of a remote substituent in the intramolecular ketene-styrene [2+2] cycloaddition of p-substituted 2-methyl-7-arylhepta-1,6-dien-1-one which produces the bicycle[3.1.1] or the bicy-cle[3.2.0] heptanones according to Bèlanger experimental results. The transition state geometries were found as an asynchronous process with a three-member ring structure and an incipient positive charge development. Kinetic and thermodynamic controls were proposed at B3LYP/6-31+G* to determine which product is most likely to form in a competence reaction. In addition, the value of the ρ experimental reaction constant was reproduced, ρ ~ -1.34.

Palavras-chave : B3LYP/6-31+G*; MP2/6-31+G*//B3LYP/6-31+G* calculations Hammett relationship; kinetic control; thermodynamic control; [2+2] cycloaddition.

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