Catalytic Synthesis of Tricyclic Quinoline Derivatives from the Regioselective Hydroamination and C−H Bond Activation Reaction of Benzocyclic Amines and Alkynes

The cationic ruthenium−hydride complex [(PCy3)2(CO)(CH3CN)2RuH]+BF4- (1) was found to be an effective catalyst for the regioselective coupling reaction of benzocyclic amines and terminal alkynes to form the tricyclic quinoline derivatives. The scope of the reaction was explored by using the catalytic system Ru3(CO)12/NH4PF6. The catalytically active cationic ruthenium−acetylide complex [(PCy3)2(CO)(CH3CN)2RuC⋮CPh]+BF4- was isolated from the reaction of 1 with phenylacetylene.