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Pure Appl. Chem., 2005, Vol. 77, No. 11, pp. 1807-1821

Kinetics of electrophile-nucleophile combinations: A general approach to polar organic reactivity

Herbert Mayr and Armin R. Ofial

Department Chemie und Biochemie der Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München, Germany

Abstract: Benzhydrylium ions (Ar2CH+) and structurally related quinone methides are employed as reference electrophiles for comparing the nucleophilicities of a large variety of compounds, e.g., alkenes, arenes, alkynes, allylsilanes, allylstannanes, enol ethers, enamines, diazo compounds, carbanions, transition-metal π-complexes, hydride donors, phosphanes, amines, alkoxides, etc., using the correlation equation log k (20 °C) = s(N + E), where s and N are nucleophile-dependent parameters and E is an electrophilicity parameter. The same equation was employed to derive the electrophilicity parameter E for different types of carbocations, cationic transition-metal π-complexes, typical Michael acceptors, and electron-deficient arenes. The E, N, and s parameters thus obtained can be used for predicting rates and selectivities of polar organic reactions.