The 13 C shieldings of the primary carbinyl carbons in cyclohexylmethanol, its acetate and methyl ether as well as those for the corresponding carbon in their 4-t-butyl derivatives have been measured at 15.1 MHz using the 'proton-decoupling' method. Similar data for the 1-methyl-4-t-butylcyclohexylcarbinols and their acetates were obtained to examine the influence of the additional methyl substituent. Possible origins of the observed conformational effects on 13 C nuclear shieldings are considered. The 1 H results for the methylene protons in these carbinyl groups are also presented and discussed. These results, which permit estimations of the conformational free energies (−ΔG°) of the —CH 2 OR groupings (R = H, Ac, Me), are presented to illustrate the 13 C approach to conformational analysis.
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Buchanan et al. (1969) studied this question.