Enantioselective cycloisomerization of 1,6-enynes to bicyclo[3.1.0]hexanes catalyzed by rhodium and benzoic acid.
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. The present cycloisomerization may involve site selective γ-hydrogen elimination. The one-pot enantioselective cycloisomerization and lactonization of 1,6-enynes, leading to bicyclic lactones, has also been accomplished.
Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology , Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
Koji
K
Masutomi
Keiichi
K
Noguchi
Ken
K
Tanaka