It has been established that a cationic Rh(I)/(S)-Segphos or (S)-DTBM-Segphos complex and benzoic acid catalyze the enantioselective cycloisomerization of 1,6-enynes, possessing carbonyl groups at the enyne linkage, to 2-alkylidenebicyclo[3.1.0]hexanes [e.g., I 竊�II in 96% yield, 81% ee in presence of Rh/(S)-Segphos/BzOH]. The present cycloisomerization may involve site selective ホウ-hydrogen elimination. The one-pot enantioselective cycloisomerization and lactonization of 1,6-enynes, leading to bicyclic lactones, has also been accomplished. [on SciFinder(R)]