Substituent-Induced1H Chemical Shifts of 3-Substituted Camphors

The high-field 1H NMR analysis of 3-substituted camphors with OH, OMe, SMe, NHMe, NMe2 and Me substituents at endo and exo positions, and also with an oxo substituent, is reported. The substituent-induced chemical shifts (SCS) obtained for these difunctional systems, including those from previous work on 3-halocamphors, were examined in view of multilinear correlations with steric and electronic parameters. The resultant data show a strong contribution from the electric field mechanism, principally for the protons closer to the substituent. Carbonyl group interference on the expected SCS for the α-proton is also observed, with less deshielding than those of substituted bornanes and norbornanes.