Influence of the spatial position of a trifluoromethyl group on the 13 C chemical shifts in the cyclohexane series

The influence of the introduction of a trifluoromethyl group on the 13 C chemical shifts in cyclohexane was examined. The two main effects observed are located at the α and γ positions relative to the carbon bearing the fluorine atoms. By comparison of the collected data it was possible to calculate the increments corresponding to the substitution of a hydrogen atom by a CF 3 group at axial or equatorial positions on the cyclohexane ring. Copyright © 2006 John Wiley & Sons, Ltd.