Conformational preference of the fluoromethyl group in some benzyl fluorides: a ¹³C N.M.R. study

Abstract

A number of model benzyl fluoride systems have been synthesized, and their proton-decoupled natural-abundance ¹³C n.m.r. spectra recorded and assigned. An analysis of the long-range five-bond coupling constants (⁵J_CF) indicates that these parameters are predominantly a manifestation of hyperconjugation involving the CF σ bond. The utilization of these parameters as conformational probes is demonstrated.