Carbon-13 nuclear magnetic resonance spectra: V—substituent interactions at 4-substituted adamantanones and bicyclo[2.2.2]octanones

The ¹³C n.m.r. data of a variety of 4_eq- and 4_ax-substituted adamantanones and bicyclo2.2.2]octanones are presented. It is shown that for a number of carbons the chemical shifts cannot be predicted by a given additivity rule. The deviations of the observed chemical shifts from the calculated ones are discussed in terms of different interaction mechanisms operating through the σ bond frameworks or through space.