1361990-66-0Relevant academic research and scientific papers
Well-Designed N-Heterocyclic Carbene Ligands for Palladium-Catalyzed Denitrative C-N Coupling of Nitroarenes with Amines
Chen, Kai,Chen, Wanzhi,Chen, Wei,Liu, Miaochang,Wu, Huayue
, p. 8110 - 8115 (2019/08/26)
The C-N bond formation is one of the fundamental reactions in organic chemistry, because of the widespread presence of amine moieties in pharmaceuticals and biologically active compounds. Palladium-catalyzed C-N coupling of haloarenes represents one of the most efficient approaches to aromatic amines. Nitroarenes are ideal alternative electrophilic coupling partners, since they are inexpensive and readily available. The denitration and cross-coupling using nitroarenes as the electrophilic partners is challenging, because of the low reactivity of the Ar-NO2 bond toward oxidative addition. We report here the C-N coupling of nitroarenes and amines using palladium/5-(2,4,6-triisopropylphenyl)imidazolylidene[1,5-a]pyridines as the catalyst. The ligands are readily available from commercial chemicals. The reaction shows broad substrate scope and functional group tolerance. The method is applicable to both aromatic and aliphatic amines, and many secondary and tertiary aromatic amines bearing various functional groups were obtained in high yields.
Sterically Hindered Amination of Aryl Chlorides Catalyzed by a New Carbazolyl-Derived P,N-Ligand-Composed Palladium Complex
Choy, Pui Ying,Kwong, Fuk Yee,Lai, Wing In,Leung, Man Pan
, p. 2678 - 2686 (2019/06/19)
A family of 2-(9 H -carbazol-9-yl)phenyl-based phosphine ligands were synthesized and their efficacy in promoting the steric hindered Buchwald-Hartwig amination was evaluated. In the presence of Pd(OAc) 2 (0.03-1.0 molpercent) associated with t
Pd-PEPPSI-IPentAn Promoted Deactivated Amination of Aryl Chlorides with Amines under Aerobic Conditions
Huang, Fei-Dong,Xu, Chang,Lu, Dong-Dong,Shen, Dong-Sheng,Li, Tian,Liu, Feng-Shou
, p. 9144 - 9155 (2018/07/21)
We report herein a highly efficient Pd-catalyzed amination by "bulky-yet-flexible" Pd-PEPPSI-IPentAn complexes. The relationship between the N-heterocyclic carbenes (NHCs) structure and catalytic properties was discussed. Sterically hindered (hetero)aryl chlorides and a variety of aliphatic and aromatic amines can be applied in this cross-coupling, which smoothly proceeded to provide desired products. The operationally simple protocol highlights the rapid access to CAr-N bond formation under mild conditions without the exclusion of air and moisture.
(IPr)Pd(pydc) (pydc = pyridine-2,6-dicarboxylate) - A highly active precatalyst for the sterically hindered C-N coupling reactions
Li, Yan-Jing,Zhang, Jin-Ling,Li, Xiao-Jian,Geng, Yu,Xu, Xiao-Hua,Jin, Zhong
, p. 12 - 20 (2013/06/27)
A new class of well-defined NHC-Pd complexes incorporating a pyridine-2-carboxylate or pyridine-2,6-dicarboxylate ligand has been synthesized. These novel complexes exhibited prominent catalytic activity in the sterically hindered C-N coupling reactions at elevated temperature, but relatively inferior reactivity at low temperature. The distinctly different reactivity of these NHC-Pd complexes was presumed to be associated with their unique structures of ancillary ligands.
Amination with Pd-NHC complexes: Rate and computational studies involving substituted aniline substrates
Hoi, Ka Hou,Calimsiz, Selcuk,Froese, Robert D. J.,Hopkinson, Alan C.,Organ, Michael G.
supporting information; experimental part, p. 145 - 151 (2012/02/04)
The amination of aryl chlorides with various aniline derivatives using the N-heterocyclic carbene-based Pd complexes Pd-PEPPSI-IPr and Pd-PEPPSI-IPent (PEPPSI=pyridine, enhanced precatalyst, preparation, stabilization, and initiation; IPr=diisopropylphenylimidazolium derivative; IPent= diisopentylphenylimidazolium derivative) has been studied. Rate studies have shown a reliance on the aryl chloride to be electron poor, although oxidative addition is not rate limiting. Anilines couple best when they are electron rich, which would seem to discount deprotonation of the intermediate metal ammonium complex as being rate limiting in favour of reductive elimination. In previous studies with secondary amines using PEPPSI complexes, deprotonation was proposed to be the slow step in the cycle. These experimental findings relating to mechanism were corroborated by computation. Pd-PEPPSI-IPr and the more hindered Pd-PEPPSI-IPent catalysts were used to couple deactivated aryl chlorides with electron poor anilines; while the IPr catalysis was sluggish, the IPent catalyst performed extremely well, again showing the high reactivity of this broadly useful catalyst. Copyright
Potassium 2,2,5,7,8-pentamethylchroman-6-oxide: A rationally designed base for Pd-catalysed amination
Hoi, Ka Hou,Organ, Michael G.
supporting information; experimental part, p. 804 - 807 (2012/03/11)
This base is just right! A new base, potassium 2,2,5,7,8- pentamethylchroman-6-oxide, for Pd-catalysed amination has been rationally designed that has sufficient basicity to efficiently deprotonate the intermediate aryl palladium ammonium complex, leading to far better rates than obtained with carbonate, which is known to be very mild. At the same time, this new base possesses minimal nucleophilicity to mitigate the degradation of base-sensitive functional groups in the starting materials and products, such as is commonly seen with potassium or sodium tert-butoxide. Copyright
