The reaction of 1-hydroxydiamantane with elemental bromine leads to consecutive cage opening and re-closure, thereby providing a straightforward approach to the class of previously unknown 1,2-disubstituted diamondoid derivatives. Functional group exchange gave, among others, chiral bidentate ligands 1,2-dihydroxy- and 1,2-diaminodiamantane. The latter was enantioseparated on gram scale with ee >98% through a single crystallization with (+)-tartaric acid.