Structure− Reactivity Effects on Primary Deuterium Isotope Effects on Protonation of Ring-Substituted α-Methoxystyrenes

WY Tsang, JP Richard

Index: Tsang, Wing-Yin; Richard, John P. Journal of the American Chemical Society, 2009 , vol. 131, # 39 p. 13952 - 13962

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Citation Number: 12

Abstract

Primary product isotope effects (PIEs) on L+ and carboxylic acid catalyzed protonation of ring-substituted α-methoxystyrenes (X-1) to form oxocarbenium ions X-2+ in 50/50 (v/v) HOH/DOD were calculated from the yields of the α-CH3 and α-CH2D labeled ketone products, determined by 1H NMR. A plot of PIE against reaction driving force shows a maximum PIE of 8.7 for protonation of 4-MeO-1 by Cl2CHCOOH (Δ G°= 1.0 kcal/mol). The ...