Discussion.-Comparison of the thermal reactions of pinane and 6, G-dimethylnorpinane shows that pinane isomerizes to a diolefin faster than G, G-dimethylnorpinane arid the diolefin from pinane cyclizes faster than the diolefin from 6, 6-diniethylnorpinane.. kcording to the mechanism proposed for the pinaiie reaction,]: L biradical is an intermediate in the formation of the diolefin. Pinane gives IV and 6, G-dimethylnorpinane gives 1'as ...