钯催化的 C–X/C–H 键与亲核试剂之间的交叉偶联反应仍然是有机合成中的主要方法。这些反应依赖于活性 LPd 0物质的原位生成。在催化条件下容易形成 LPd 0物质的空气稳定钯 (II) 预催化剂已被确定为有效的预催化剂。在碱存在下,烷基胺配体可作为钯 (II) 络合物的潜在还原配体,通过一系列 β-氢消除和碱促进的氢化钯还原消除。一系列空气稳定的 ( t Bu 2 PNp)Pd(amine)Cl 2(Np = 新戊基) 配合物是用一系列结构不同的伯胺和仲胺配体合成的。这些络合物允许分析胺配体结构对芳基卤化物和苯胺衍生物交叉偶联中催化剂性能的影响。胺配体的特性对催化剂活性和寿命有显着影响。具有伯正烷基胺配体的预催化剂提供最活泼的催化剂。使用 ( t Bu 2 PNp)Pd( n -丁胺)Cl 2作为预催化剂的反应在室温下 1 小时内提供了优异的产率。此外,(Np 3 P)Pd(正丁胺)Cl
Palladium-catalyzed synthesis of carbazoles from N-(2-halophenyl)-2,6-diisopropylanilines via C–C cleavage
作者:Anthony R. Chianese、Scott L. Rogers、Hanna Al-Gattas
DOI:10.1016/j.tetlet.2010.02.098
日期:2010.4
The synthesis of 1-isopropyl-substituted carbazoles by the palladium-catalyzed dealkylative cyclization of N-(2-halophenyl)-2,6-diisopropylanilines is described. The reaction involves intramolecular C–C bond formation, coupled with the cleavage of a C–X bond and a C–C bond, and is proposed to proceed through the formation of a dearomatized intermediate.
Pd catalyzed coupling of 1,2-dibromoarenes and anilines: formation of N,N-diaryl-o-phenylenediamines
作者:Todd Wenderski、Kenneth M. Light、Doug Ogrin、Simon G. Bott、C. Jeff Harlan
DOI:10.1016/j.tetlet.2004.07.116
日期:2004.9
1,2-Dibromoarenes were coupled with aniline derivatives to yield N,N-diaryl-o-phenylenediamines in moderate to good yield using a palladium/phosphine or palladium/carbene catalyst system. Under similar conditions, 1, 2,4,5- tetrabromobenzene was coupled with aniline derivatives to produce the corresponding tetrasubstituted derivatives which are oxidized on workup to yield azophenines. The sequential reaction of two different anilines with 1-chloro-2-iodobenzene afforded mixed N,N-diaryl-ophenylenediamines. (C) 2004 Elsevier Ltd. All rights reserved.