Ruthenium(II)/N-Heterocyclic Carbene Catalyzed [3+2] Carbocyclization with Aromatic N[BOND]H Ketimines and Internal Alkynes


  • Financial support for this work was provided by ND EPSCoR seed grant (EPS-0447679) and NIH (Grant Number 2P20 RR015566) from the National Center for Research Resources. We thank NSF-CRIF (CHE-0946990) for the purchasing an X-ray diffractometer for the department. We also thank Dr. John Bagu and Daniel Wanner for assistance with NMR experiments.


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Convenient and highly efficient: Indenamines were synthesized using the title reaction, which occurs at ambient temperature, in the absence of oxidants or other metal salts, and in nonpolar solvents. A proposed mechanism involves imine-directed activation of an aromatic C[BOND]H bond, alkyne insertion, and carbocyclization by intramolecular imine insertion into Ru–alkenyl linkages.