Organofluorine chemistry : difluoromethylene motifs spaced 1,3 to each other imparts facial polarity to a cyclohexane ring

Abstract

2,2-Dimethyl-5-phenyl-1,1,3,3-tetrafluororocyclohexane has been prepared and characterised as an example of a facially polarised cyclohexane containing 1,3 related CF2 groups. The dipolar nature of the ring arises from the axial orientation of two of the C-F bonds pointing in the same direction, and set by the chair conformation of the cyclohexane. This electrostatic profile is revealed experimentally both in the solid-state (X-ray) packing of the rings and by solution (NMR) in different solvents. A computationally derived electrostatic profile of this compound is consistent with a more electronegative and a more electropositive face of the cyclohexane ring. This placing of CF2 groups 1,3 to each other in a cyclohexane ring is introduced as a new design strategy which could be applicable to the preparation of polar hydrophobic cyclohexane motifs.