¹H NMR utilization of through‐space effects: III—configuration of oximes and analogous compounds

Abstract

Abstract The configurational assignment of Z and E nitrogen derivatives ( ) of 3,5,5‐trimethyl‐2‐cyclohexen‐1‐one was made taking into consideration the through‐space effects on oxime, O ‐methyloxime, dimethylhydrazone, tert ‐butylimine, N , N , N ‐trimethylhydrazonium iodide and oxime hydrochloride derivatives. The relationship between the magnitude of the chemical shifts of the α‐protons and the dihedral angle formed by the α‐CH bond and the CNOH plane was interpreted in terms of the geometrical dependence of the electric field effect. For the different Y substituents, the change in chemical shift between the Z and the E configuration of the proton near the functional group was mainly dependent on the electric field effect.