Palladium-Catalyzed Amidation and Amination of (Hetero)aryl Chlorides under Homogeneous Conditions Enabled by a Soluble DBU/NaTFA Dual-Base System
作者:Gregory L. Beutner、John R. Coombs、Rebecca A. Green、Bahar Inankur、Dong Lin、Jun Qiu、Frederick Roberts、Eric M. Simmons、Steven R. Wisniewski
DOI:10.1021/acs.oprd.9b00196
日期:2019.8.16
The palladium-catalyzed coupling of aryl and heteroaryl chlorides with primary amides under mild homogeneous reaction conditions is reported. Successful C–N coupling is enabled by the use of a unique “dual-base” system consisting of DBU and NaTFA, which serve as proton acceptor and halide scavenger, respectively, using low catalyst loadings (0.5 mol %) with readily available, air-stable palladium precatalysts
Facile <i>N</i>-Arylation of Amines and Sulfonamides and <i>O</i>-Arylation of Phenols and Arenecarboxylic Acids
作者:Zhijian Liu、Richard C. Larock
DOI:10.1021/jo0602221
日期:2006.4.1
An efficient, transition-metal-free procedure for the N-arylation of amines, sulfonamides, and carbamates and O-arylation of phenols and carboxylicacids has been achieved by allowing these substrates to react with a variety of o-silylaryl triflates in the presence of CsF. Good to excellent yields of arylated products are obtained under very mild reaction conditions. This chemistry readily tolerates
Synthesis of Di(hetero)arylamines from Nitrosoarenes and Boronic Acids: A General, Mild, and Transition-Metal-Free Coupling
作者:Silvia Roscales、Aurelio G. Csákÿ
DOI:10.1021/acs.orglett.8b00473
日期:2018.3.16
The synthesis of di(hetero)arylamines by a transition-metal-free cross-coupling between nitrosoarenes and boronicacids is reported. The procedure is experimentally simple, fast, mild, and scalable and has a wide functional group tolerance, including carbonyls, nitro, halogens, free OH and NH groups. It also permits the synthesis of sterically hindered compounds.
Development of an Aryl Amination Catalyst with Broad Scope Guided by Consideration of Catalyst Stability
作者:Scott D. McCann、Elaine C. Reichert、Pedro Luis Arrechea、Stephen L. Buchwald
DOI:10.1021/jacs.0c06139
日期:2020.9.2
We have developed a new dialkylbiaryl monophosphine ligand, GPhos, that supports a palladium catalyst capable of promoting carbon-nitrogen cross-coupling reactionsbetween a variety of primary amines and aryl halides; in many cases these reactions can be carried out at room temperature. The reaction development was guided by the idea that the productivity of catalysts employing BrettPhos-like ligands
The Quest for the Ideal Base: Rational Design of a Nickel Precatalyst Enables Mild, Homogeneous C–N Cross-Coupling
作者:Richard Y. Liu、Joseph M. Dennis、Stephen L. Buchwald
DOI:10.1021/jacs.0c00286
日期:2020.3.4
Palladium-catalyzed amination reactions using soluble organic bases have provided a solution to the many issues associated with heterogeneous reaction conditions. Still, homogeneous C-N cross-coupling approaches cannot yet employ bases as weak and economical as trialkylamines. Furthermore, organic base-mediated methods have not been developed for Ni(0/II) catalysis, despite some advantages of such systems
使用可溶性有机碱的钯催化胺化反应为与多相反应条件相关的许多问题提供了解决方案。尽管如此,均相 CN 交叉偶联方法尚不能使用与三烷基胺一样弱且经济的碱。此外,尽管有机碱介导的方法与类似的 Pd 基催化剂相比具有一些优势,但尚未开发出用于 Ni(0/II) 催化的有机碱介导方法。我们设计了一种新的空气稳定且易于制备的 Ni(II) 预催化剂,其带有缺电子的双齿膦配体,能够使用三乙胺 (TEA) 作为碱使芳基三氟甲磺酸酯与芳基胺交叉偶联。该方法可以容忍空间拥挤的偶联伙伴,以及带有碱和亲核试剂敏感官能团的偶联伙伴。借助密度泛函理论 (DFT) 计算,我们确定缺电子辅助配体降低了 Ni 键合胺的 pKa 和从所得 Ni(II)-酰胺络合物还原消除的障碍。此外,我们确定,由于空间因素,排除 Ni 催化剂和碱之间的路易斯酸碱络合对于避免催化剂抑制很重要。