Empirical Substituent Parameters for <i>E</i>/<i>Z</i> Equilibrium Constants

Abstract

Abstract A set of substituent parameters λ d is proposed which permits the prediction of E / Z equilibrium constants for olefins, enamines, Schiff bases, hydrazones, semicarbazones, oximes, and nitrones. The set includes values for the „non‐bonded”︁ electron pairs and the nitrone oxygen as well as for amino or phenyl groups coplanar and orthogonal to the double bond. Ketone anils prefer a perpendicular phenyl group. Principal limitations of the very simple heuristic model are discussed. The model is also applied to the „ cis ”︁‐ and „ ortho ”︁‐effects, enolates, and Schiff bases of cyclic and bicyclic ketones.