Konformationsuntersuchungen mit Hilfe der 13C-NMR-Spektroskopie. IV. Additive Berechnung der 13C-chemischen Verschiebungen in 2-Brom-cycloalkanolen und 2-Brom-1-methoxy-cycloalkanen unterschiedlicher Ringgröße

Conformational Investigations by Means of ¹³C-N.M.R.Spectroscopy. IV. Additive Calculation of the ¹³C-N.M.R. Chemical Shifts in 2-Bromo-cycloalkanoles and 2-Bromo-1-methoxy-cycloalkanes of Different Ring Size The ¹³C-n.m.r. spectra of a series of bromo-cycloalkanes, cycloalkanoles, methoxy-cycloalkanes, trans-2-bromo-cycloalkanoles and trans-2-bromo-1-methoxy-cycloalkanes (ring size n = 5, 6, 7, 8, 12) as well as cis-2-bromo-cyclododecanol and cis-2-bromo-1-methoxycyclododecane are obtained and assigned. The ¹³C-chemical shifts of the monosubstituted compounds have been used to estimate the substituent effects of bromo, hydroxy and methoxy groups to the α-, β- and γ-position. Using these shift parameters, the ¹³C-chemical shifts of the vicinal disubstituted compounds are calculated in an additive incremental manner. These ¹³C-chemical shifts have been compared with the experimental values and the differences are discussed with respect to the magnitude of the deviations from additivity with the dimension of steric and electronic interaction of the vicinal substituents.