Reaction of N-lithioethylenediamine on the 11-membered monocyclic sesquiterpenoids zerumbone (I) and zerumbol (II) has been studied. Zerumbone undergoes polymerization in the presence of the reagent whereas zerumbol via transannular cyclization-oxidation is converted to the bicyclic ketone, 2-keto-Δ5; 6, 4; 11-bicyclo (6: 3: 0) undecane (VII). Its structure has been rigorously established by chemical degradation and spectral studies.
