2-t-Butyl-exo-norbornyl p-nitrobenzoate is an extremely reactive compound, undergoing solvolysis 2.8106 times faster than t-butyl p nitrobenzoate. The endo isomer is about 500 times less reactive. In contrast to the unsubstituted norbornyl system, which gives almost exclusively exo product, both t-butyl isomers give about 5% of the endo product