Nucleophilicity Parameters of Arylsulfonyl-Substituted Halomethyl Anions

Li, Zhen; Chen, Quan; Mayer, Peter und Mayr, Herbert (2017): Nucleophilicity Parameters of Arylsulfonyl-Substituted Halomethyl Anions. In: Journal of Organic Chemistry, Bd. 82, Nr. 4: S. 2011-2017

Abstract

The rates of the reactions of the arylsulfonyl-substituted carbanions carrying a-chloro and a-bromo substituents (1a-e) with quinone methides 2a-g and benzylidenemalonates 2h and 2i in DMSO were determined photometrically at 20 degrees C. The reactions were performed under pseudo-first-order conditions, and the second-order rate constants were obtained as the slopes of the plots of the pseudo-first-order rate constants versus the concentrations of the reactants used in excess. The second order rate constants correlate linearly with the parameters E of the reference electrophiles according to the linear free energy relationship log k(2)(20 degrees C) = s(N)(N + E), which allowed us to derive the nucleophile-specific parameters N and s(N) of carbanions la-e. The resulting nucleophilicity parameters N (23 < N < 29) reveal the title compounds to be among the most reactive nucleophiles so far integrated on our comprehensive nucleophilicity scale.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Chemie und Pharmazie > Department Chemie
• Themengebiete: 500 Naturwissenschaften und Mathematik > 540 Chemie
• ISSN: 0022-3263
• Sprache: Englisch