Substituent effects on long range proton-proton couplings in 4-substituted bornanones

Long range proton–proton coupling constants between H3exo and H5exo have been measured in a series of 4-substituted bornanones. Correlation between the magnitudes of 4J3exo–5exo and the inductive linear free energy σI has been obtained. 4-Substituted bornanone nitrimines exhibit diminished values of 4J3exo–5exo with respect to the parent ketone.