Title

Carbon Acidity. 53. Kinetic and Equilibrium Acidities of Fluorinated Bicycloalkanes

Abstract

Base-catalyzed tritium exchange kinetics in methanolic sodium methoxide are reported for lH-4-Y-perfluorobicyclo[2.2.1]heptanes, Y = F (1), H (2), CH3 (3), Br (4), I (5), CF3 (6), 1H-perfluorobicyclo[2.2.2]octane (7), and lH-perfluorobicyclo[2.2.1]hept-2-ene (8). The primary isotope effect for 2 is weak. Equilibrium cesium ion pair acidities are reported for compounds 1,2,3,6,7, and 8 in cyclohexylamine relative to conjugated hydrocarbon indicators. A Brønsted plot of the kinetic and equilibrium acidities has a slope close to unity and is used to assign pK values to related halogenated carbon acids. The acidities of the fluorinated bicycloalkanes can be accommodated completely by a classical field effect as modeled by Kirkwood-Westheimer calculations.

Department(s)

Chemistry

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1976 American Chemical Society (ACS), All rights reserved.


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