Here's a fairly simple procedure for isolating the active component of catnip from the dried herb.
It should be somewhat safe (it does involve some somewhat dangerous chemicals like toluene [paint thinner], however), and would probably be doable at home. You can also probably find some good procedure for isolating caffeine on google.
These aren't chemical reactions, but performing these isolations is most definitely chemistry. Often in organic chemistry, we spend more time isolating the product of the reaction, than on the chemical reaction itself.