Scope and Mechanistic Study of the Ruthenium-Catalyzed ortho-C−H Bond Activation and Cyclization Reactions of Arylamines with Terminal Alkynes

Authors

Chae S. Yi, Marquette UniversityFollow
Young Yun, Marquette UniversityFollow

Document Type

Article

Language

eng

Format of Original

7 p.

Publication Date

2005

Publisher

American Chemical Society

Source Publication

Journal of the American Chemical Society

Source ISSN

0002-7863

Original Item ID

DOI: 10.1021/ja055608s

Abstract

The cationic ruthenium hydride complex [(PCy₃)₂(CO)(CH₃CN)₂RuH]⁺BF₄^- was found to be a highly effective catalyst for the C−H bond activation reaction of arylamines and terminal alkynes. The regioselective catalytic synthesis of substituted quinoline and quinoxaline derivatives was achieved from the ortho-C−H bond activation reaction of arylamines and terminal alkynes by using the catalyst Ru₃(CO)₁₂/HBF₄·OEt₂. The normal isotope effect (k_CH/k_CD = 2.5) was observed for the reaction of C₆H₅NH₂ and C₆D₅NH₂ with propyne. A highly negative Hammett value (ρ = −4.4) was obtained from the correlation of the relative rates from a series of meta-substituted anilines, m-XC₆H₄NH₂, with σ_p in the presence of Ru₃(CO)₁₂/HBF₄·OEt₂ (3 mol % Ru, 1:3 molar ratio). The deuterium labeling studies from the reactions of both indoline and acyclic arylamines with DC⋮CPh showed that the alkyne C−H bond activation step is reversible. The crossover experiment from the reaction of 1-(2-amino-1-phenyl)pyrrole with DC⋮CPh and HC⋮CC₆H₄-p-OMe led to preferential deuterium incorporation to the phenyl-substituted quinoline product. A mechanism involving rate-determining ortho-C−H bond activation and intramolecular C−N bond formation steps via an unsaturated cationic ruthenium acetylide complex has been proposed.

Comments

Accepted version. Journal of the American Chemical Society, Vol. 127, No. 48 (2005): 17000-17006. DOI. © 2005 American Chemical Society. Used with permission.

Recommended Citation

Yi, Chae S. and Yun, Young, "Scope and Mechanistic Study of the Ruthenium-Catalyzed ortho-C−H Bond Activation and Cyclization Reactions of Arylamines with Terminal Alkynes" (2005). Chemistry Faculty Research and Publications. 407.
https://epublications.marquette.edu/chem_fac/407