Polar substituent effects in the bicyclo[2.2.2]octane ring system: A 19F NMR study of some 4‐substituted bicyclo[2.2.2]octane‐1‐carbonyl fluorides

Abstract

AbstractFluorine‐19 substituent chemical shifts (SCS) are reported for a series of 4‐substituted bicyclo[2.2.2]octane‐1‐carbonyl fluorides containing a limited but a representative number of dipolar substituents. The 19F SCS, which cover a very narrow range (<0.5 ppm), are found to correlate poorly against polar field parameters (σF). Polar field susceptibility parameters (ρF) for the fluorine probe were determined indirectly and their origin is briefly discussed in the light of the carbonyl 13C SCS which reflect π polarization of the COF group.