Abstract N-Protected tropenone derivatives 3, prepared from the respective pyrroles 5 and tetrabromoacetone (6), were used as starting materials for desymmetrization by hydroboration of the CC double bond. Hydroboration of 3a with (-)-(Ipc) 2 BH followed by oxidation, however, gave the desired 6-hydroxylated product 4a only in low yield due to byproduct formation. After acetalization of the carbonyl group in 3, the corresponding ...