Substituent effects by ¹⁹F nuclear magnetic resonance: Polar and π-electron effects

Abstract

A number of model substituted bicyclic aryl fluorides, including three new fluorobenzocycloalkenes, have been synthesized and their fluorine- 19 spectra measured. An analysis of the data leads to the important conclusion that electrostatic-field effects play an important role in determining aryl ¹⁹F chemical shifts. Further the relative π-electron distributions of several benzocycloalkenes are indicated.