1361990-66-0Relevant articles and documents
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.
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.
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
