Amidation of Unfunctionalized Hydrocarbons Catalyzed by Ruthenium Cyclic Amine or Bipyridine Complexes

• Published in: Journal of organic chemistry Vol. 65; no. 23; pp. 7858 - 7864
• Main Authors: Au, Sze-Man, Huang, Jie-Sheng, Che, Chi-Ming, Yu, Wing-Yiu
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 17-11-2000
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo000881s

Selective amidation of simple hydrocarbons with pre-isolated and in-situ formed iminoiodanes catalyzed by ruthenium complexes [RuIII(Me3tacn)(CF3CO2)3·H2O] (2b, Me3tacn = N,N ‘ ,N ‘ ‘-trimethyl-1,4,7-triazacyclononane) and cis-[RuII(6,6‘-Cl2bpy)2Cl2] (3, 6,6‘-Cl2bpy = 6,6‘-dichloro-2,2‘-bipyridine) was investigated. With PhINTs as nitrogen source, both catalysts efficiently promote the amidation of adamantane, cyclohexene, ethylbenzene, cumene, indan, tetralin, and diphenylmethane to afford N-substituted sulfonamides in 80−93% yields with high selectivity. Competitive amidations of para-substituted ethylbenzenes and kinetic isotope effect for the amidation of cyclohexene/cyclohexene-d 10 suggest that the amidation processes probably proceed via the hydrogen abstraction by a reactive RuNTs species to form a carboradical intermediate. The amidation with PhI(OAc)2/TsNH2 gave results comparable to those obtained with PhINTs. Extension of the “PhI(OAc)2/TsNH2 + catalyst 2b or 3” protocol to MeSO2NH2 and PhCONH2 with ethylbenzene as substrate produced the corresponding N-substituted amides in up to 89% yield.