51580-77-9Relevant academic research and scientific papers
Paracyclophane-based monophosphine ligand for palladium-catalyzed cross-coupling reactions of aryl chlorides
Ruan, Jiwu,Shearer, Lee,Mo, Jun,Bacsa, John,Zanotti-Gerosa, Antonio,Hancock, Fred,Wu, Xiaofeng,Xiao, Jianliang
experimental part, p. 3236 - 3242 (2009/10/23)
A new [2.2]paracyclophane-based electron-rich and sterically bulky monophosphine ligand has been synthesized by an efficient and straightforward method. When combined with palladium, this ligand shows excellent performance in the Buchwald-Hartwig amination and Suzuki-Miyaura coupling reactions of various aryl chlorides. In both types of reactions, ortho-substituted, deactivated aryl chlorides are shown to be viable substrates. However, the Suzuki-Miyaura coupling appears to be easier, with palladium loading at 0.1 mol% being feasible. The Royal Society of Chemistry 2009.
PARACYCLOPHANE-BASED LIGANDS, THEIR PREPARATION AND USE IN CATALYSIS
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Page/Page column 12, (2009/04/25)
A substituted paracyclophane is described of formula (I) wherein X1 and X2 are linking groups comprising between 2 to 4 carbon atoms, Y1 and Y2 are selected from the group consisting of hydrogen, halide, oxygen, nitrogen, alkyl, cycloalkyl, aryl or heteroaryl and Z is a substituted or unsubstituted alkyl group, aryl group or heteroaryl group. Preferably X1 and X2 are -(C2H4)- and Z is a substituted aryl group. The substituted paracyclophane provides transition metal catalysts that are useful in C-C and C-N bond formation and asymmetric hydrogenation reactions.
Simple, efficient catalyst system for the palladium-catalyzed amination of aryl chlorides, bromides, and triflates
Wolfe, John P.,Tomori, Hiroshi,Sadighi, Joseph P.,Yin, Jingjun,Buchwald, Stephen L.
, p. 1158 - 1174 (2007/10/03)
Palladium complexes supported by (o-biphenyl)P(t-Bu)2 (3) or (o- biphenyl)PCy2 (4) are efficient catalysts for the catalytic amination of a wide variety of aryl halides and triflates. Use of ligand 3 allows for the room-temperature catalytic amination of many aryl chloride, bromide, and triflate substrates, while ligand 4 is effective for the amination of functionalized substrates or reactions of acyclic secondary amines. The catalysts perform well for a large number of different substrate combinations at 80-110 °C, including chloropyridines and functionalized aryl halides and triflates using 0.5-1.0 mol % Pd; some reactions proceed efficiently at low catalyst levels (0.05 mol % Pd). These ligands are effective for almost all substrate combinations that have been previously reported with various other ligands, and they represent the most generally effective catalyst system reported to date. Ligands 3 and 4 are air-stable, crystalline solids that are commercially available. Their effectiveness is believed to be due to a combination of steric and electronic properties that promote oxidative addition, Pd-N bond formation, and reductive elimination.
Palladium-catalyzed amination of aryl bromides utilizing arene-chromium complexes as ligands
Kamikawa, Ken,Sugimoto, Suguru,Uemura, Motokazu
, p. 8407 - 8410 (2007/10/03)
The arene - chromium complexes of o-diphenylphosphino α- phenylethylamine or α-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 α-(o-diphenylphosphino)phenylethylamine and methyl α-(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.
Condensations of 1,4-Cyclohexanediones and Secondary Aromatic Amines. The Formation of Alkyldiarylamines and Triarylamines
Haga, Kazuo,Oohashi, Masayuki,Kaneko, Ryohei
, p. 1586 - 1590 (2007/10/02)
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 ? values gave -2.0 as the ρ value.In separate reactions, however, a different tendency is noted for the yield, that is, the ease of reactions with p-chloro and p-nitro derivatives.This discrepancy is explained in terms of acidities of the conjugate acids of the amines used as the actual catalysts.
