AbstractUpon treatment with three equivalents of methyllithium in ether at room temperatureexo‐3‐d‐norcamphor tosylhydrazone gave norbornene which retained 21% of the deuterium andexo‐3‐d‐apocamphor tosylhydrazone gave apobornylene which retained 50% of the deuterium based on nmr and mass spectral analysis. In both casesexo‐elimination is favored when the primary isotope effect is considered. The relatively low selectivity betweenexo‐andendo‐elimination as compared with that observed in solvolytic studies was tentatively rationalized by the carbarion character of the transition state leading to proton abstra