Condensations of 1,4-Cyclohexanediones and Secondary Aromatic Amines. The Formation of Alkyldiarylamines and Triarylamines
作者:Kazuo Haga、Masayuki Oohashi、Ryohei Kaneko
DOI:10.1246/bcsj.57.1586
日期:1984.6
Condensation of 1,4-cyclohexanedione with N-alkylarylamines gives N-alkyl-N-arylanilines, and that with diarylamines gives triarylamines. A mechanism involving dehydration of monoenamines of the 1,4-dione is proposed for the reaction. Relative rates of substituted N-ethylanilines on competitive reactions plotted vs. Hammet’s σ values gave −2.0 as the ρ value. In separate reactions, however, a different
Palladium-Catalyzed Amination of Aryl Bromides Utilizing Arene−Chromium Complexes as Ligands
作者:Ken Kamikawa、Suguru Sugimoto、Motokazu Uemura
DOI:10.1021/jo981327+
日期:1998.11.1
The arene-chromium complexes of o-diphenylphosphino alpha-phenylethylamine or a-phenylethyl methyl ether derivatives were examined with regard to their activity as ligands for palladium(0)-catalyzed aryl amination of aryl bromides with a variety of amines. Both steric and electronic factors were found to be significant for the efficient palladium-catalyzed aryl amination reactions. Modulation of the inductive capacity of the arylphosphine atom was achieved by photoinduced ligand exchange of one carbonyl of the chromium tripode in the presence of electron-donating triphenylphosphine or phosphite. Among these arene-chromium ligands, the use of the monophosphineor monophosphite-(dicarbonyl)chromium of N,N-dimethyl alpha-(o-diphenylphosphino)phenylethylamine and methyl alpha-(o-diphenylphosphino)phenylethyl ether produced the palladium(0)-catalyzed aryl amination products with cyclic amines or acyclic secondary amines in high yields; the corresponding strong electron-withdrawing tricarbonylchromium complex resulted in a modest yield of the aryl amination.
Palladium-Catalyzed Amination of Aryl Bromides: Use of Phosphinoether Ligands for the Efficient Coupling of Acyclic Secondary Amines
作者:Jean-François Marcoux、Seble Wagaw、Stephen L. Buchwald