Carbon-13 Magnetic Resonance. IX. The Methylcyclohexanes

Abstract

Carbon-13 chemical shift data were secured on 15 methylcyclohexanes using the proton-decoupling technique. Spectral assignments are made with the aid of additive parameters derived from compounds in which unequivocal assignments are possible. A factor analysis was carried out to obtain more accurate chemical shift parameters characteristic of detailed geometrical and conformational features found in this class of compounds. These parameters are used to characterize the spectra of three compounds which exist to a significant extent in more than one form, and their conformational energies are estimated. The relationship between chemical shift and the rotation of vicinal methyls to relieve steric strain is briefly considered. © 1967, American Chemical Society. All rights reserved.