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Which Factors Control the Nucleophilic Reactivities of Enamines?
Author(s) -
Timofeeva Daria S.,
Mayer Robert J.,
Mayer Peter,
Ofial Armin R.,
Mayr Herbert
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201705962
Subject(s) - chemistry , nucleophile , electrophile , reactivity (psychology) , marcus theory , equilibrium constant , reaction rate constant , computational chemistry , lewis acids and bases , gibbs free energy , aryl , thermodynamics , ion , organic chemistry , kinetics , catalysis , alkyl , medicine , physics , alternative medicine , pathology , quantum mechanics
Abstract Changes in rate constants, equivalent to changes in Gibbs energies of activation Δ G ≠ , are commonly referred to as kinetic effects and differentiated from thermodynamic effects (Δ r G °). Often, little attention is paid to the fact that structural effects on Δ G ≠ are composed of a thermodynamic (Δ r G °) and a truly kinetic (intrinsic) component (Δ G 0 ≠ ), as expressed by the Marcus equation. Rate and equilibrium constants have been determined for a number of reactions of enamines with benzhydrylium ions (Aryl 2 CH + ), which has allowed the determination of Marcus intrinsic barriers and a differentiated analysis of structure–reactivity relationships. To our knowledge, this is the first report in which the Lewis basicity of a π CC bond towards carbon‐centered Lewis acids (for example, carbenium ions) has quantitatively been determined. The synthesis, structures, and properties of deoxybenzoin‐derived enamines ArCH=C(Ph)NR 2 , which have been designed as reference nucleophiles for the future quantification of electrophilic reactivities, are explicitly described.