LONG-RANGE PROTON-CARBON COUPLING-CONSTANTS .2. NORBORNENE SYSTEMS

Long-range proton-carbon coupling constants, (n)J(CH), were measured f or some simple norbornene derivatives. Among the influence of substitu tion pattern, a study of the experimental influence of the double bond in the norbornene skeleton on (2)J(CH) and (3)J(CH) was made, taking into account the previously published experimental data for analogous saturated systems. These experimental data show that structural groups which are several bonds away from the coupling sites, but close in sp ace, can provide important alternative mechanisms for transmission of the heteronuclear coupling.