Intramolecular OH/π versus C-H/O H-Bond-Dependent Conformational Control about Aryl-C(sp3) Bonds in Cannabidiol Derivatives.

Conformational control in cannabidiol derivatives has been studied by NMR, XRD, and DFT. The stabilization of their axial M and P conformations about the aryl-C(sp3) bond is an effect of competing intramolecular OH/π and CH/O H-bonds. In a nonpolar solvent and in the solid state, the OH/π bond is a determinant of the M conformation. In polar solvents, the CH/O H-bond shifts the equilibrium toward the P conformer because of the breaking of the OH/π bond.