Conformation of non‐aromatic ring compounds. Part 68. The calculation of dihedral angles from vicinal proton coupling constants in six‐membered ring compounds. Part 2

Abstract

AbstractFor six‐membered ring compounds having a −CH2‐CH2‐ fragment for which four vicinal coupling constants follow from the NMR spectrum (ABCD type), the ratio R = (Jtrans + J′trans/(Jcis + J′cis is equated to the ring torsional angle ψ in that fragment. The ψ values calculated from experimental coupling constants of trans‐2,3‐dichloro‐1,4‐dioxane (I) and ‐oxathiane (II), 2‐p‐chlorophenyl‐1,3‐dioxane (III), 2‐phenyl‐1,3‐dithiane (IV), trimethylene sulfite (V) and 2‐oxo‐2‐phenoxy‐1,3,2‐dioxaphosphorinane (VI) show an excellent agreement with the corresponding torsional angles obtained from X‐ray diffraction data.