1-acetylvinyl acrylates: new captodative olefins bearing an internal probe for the evaluation of the relative reactivity of captodative against electron-deficient double bonds in Diels-Alder and Friedel-Crafts reactions

Journal of the Brazilian Chemical Society

Instituto Politécnico Nacional, México, Mexico¹  Tamariz, Joaquín¹  Jiménez-Vázquez, Hugo A.¹  Herrera, Rafael¹  Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mexico¹  Söderberg, Björn C. G.¹  Delgado, Francisco¹  West Virginia University, Morgantown, USA¹ 

关键词: captodative olefins;    Friedel-Crafts;    Diels-Alder cycloaddition;    transition state calculations;   

DOI  :  10.1590/S0103-50532005000300021

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

The captodative olefins 1-acetylvinyl esters of methacrylic and trans-crotonic acids, 3a and 3b, have been prepared. The presence of a second double bond in the molecule, acting as an internal probe, allowed us to compare their relative reactivity in Diels-Alder and Friedel-Crafts reactions. The reactivity was evaluated with cyclopentadiene (6) as diene in Diels-Alder cycloadditions, and with furan (9) and thiophene (10) as heteroaromatic Friedel-Crafts substrates. In both processes, the captodative enone double bond proved to be more reactive than that in the acrylic moiety. FMO theory accounted for this chemoselectivity as a consequence of the major p contribution of the enone to the LUMO of these molecules. The slight exo stereoselectivity observed in the cycloaddition to 6 parallels the higher stability of the corresponding transition state, according to the results of B3LYP/6-311G(d,p) calculations.

【 授权许可】

Unknown