Use of Linear Free Energy Relationships (LFERs) to Elucidate the Mechanisms of Reaction of a γ-Methyl-β-alkynyl and an ortho-Substituted Aryl Chloroformate Ester

International Journal of Molecular Sciences

Malcolm J. D’Souza¹  Jaci A. Knapp¹  Gabriel A. Fernandez-Bueno¹ 

[1] Department of Chemistry, Wesley College, 120 N. State Street, Dover, DE 19901, USA; E-Mails:

关键词: solvolysis;    nucleophilicity;    ionizing power;    γ-Methyl-β-alkynyl chloroformate;    2-butyn-1-yl-chloroformate;    aryl chloroformate;    2-methoxyphenyl chloroformate;    Grunwald-Winstein equation;    Linear Free Energy Relationships (LFERs);   

DOI  :  10.3390/ijms13010665

来源: mdpi

【 摘 要 】

The specific rates of solvolysis of 2-butyn-1-yl-chloroformate (1) and 2-methoxyphenyl chloroformate (2) are studied at 25.0 °C in a series of binary aqueousorganic mixtures. The rates of reaction obtained are then analyzed using the extended Grunwald-Winstein (G-W) equation and the results are compared to previously published G-W analyses for phenyl chloroformate (3), propargyl chloroformate (4), p-methoxyphenyl choroformate (5), and p-nitrophenyl chloroformate (6). For 1, the results indicate that dual side-by-side addition-elimination and ionization pathways are occurring in some highly ionizing solvents due to the presence of the electron-donating γ-methyl group. For 2, the analyses indicate that the dominant mechanism is a bimolecular one where the formation of a tetrahedral intermediate is rate-determining.

【 授权许可】

CC BY   
© 2012 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.