使用电子供体从相应的芳基卤化物生成芳基自由基,然后与芳烃进行分子内环化,可能是当代联芳基合成的重要进步。本文报道了一种绿色且实用的合成方案,用于获取各种六元和七元联芳基磺胺类化合物,尤其是具有游离 NH 基团的化合物,包括克级合成的演示。次硫酸根阴离子自由基 (SO 2 –• ),由试剂雕白粉或连二亚硫酸钠 (Na 2 S 2 O 4),被发现是从芳基卤化物形成芳基自由基的关键单电子转移剂,其在分子内芳基化后得到具有良好至优异产率的联芳基磺胺。该方法的特点是产生仍未开发的芳基自由基,使用廉价且易于获得的工业试剂,以及无过渡金属、温和和绿色的反应条件。
Chemoselective Reductive Amination of Aldehydes and Ketones by Dibutylchlorotin Hydride-HMPA Complex
作者:Toshihiro Suwa、Erika Sugiyama、Ikuya Shibata、Akio Baba
DOI:10.1055/s-2000-6273
日期:——
Reductive amination of various aldehydes and ketones has been performed effectively by pentacoordinate chloro-substituted tin hydride complex, Bu2SnClH-HMPA. The tin reagent worked particularly well for the case using weakly basic aromatic amines as starting substrates. Stoichiometric amounts of a substrate and a reducingagent were adequate for the reaction. The Sn-Cl bond in the complex plays an
A mild and efficient method for N-alkylation of aromatic amines with various acetals such as aryl, alkyl, cyclic and acyclic acetals was developed. A number of aromatic amines bearing electron-donating or electron-withdrawing substituents were directly alkylated by acetals with excellent yields. The method uses a catalytic amount of I2 and triethylsilane as the hydride source without a metal present
A Short Approach to N-Aryl-1,2,3,4-tetrahydroisoquinolines from N-(2-Bromobenzyl)anilines via a Reductive Amination/Palladium-Catalyzed Ethoxyvinylation/Reductive N-Alkylation Sequence
作者:Franz Bracher、Carina Glas、Ricky Wirawan
DOI:10.1055/s-0040-1706002
日期:2021.6
Starting from readily available ortho-brominated aromatic aldehydes and primary aromatic amines, condensation of these building blocks under reductive conditions gives N-aryl 2-bromobenzylamines. The C-3/C-4-unit of the tetrahydroisoquinoline is introduced using commercially available 2-ethoxyvinyl pinacolboronate under Suzuki conditions. Finally, the obtained crude ortho-ethoxyvinyl benzylamines are cyclized
An efficient catalytic system for the alkylation of amines with either alcohols or amines undermildconditions has been developed, using cyclometallated iridium complexes as catalysts. The method has broad substrate scope, allowing for the synthesis of a diverse range of secondary and tertiary amines with good to excellent yields. By controlling the ratio of substrates, both mono‐ and bis‐alkylated
Alkyltelluro Substitution Improves the Radical-Trapping Capacity of Aromatic Amines
作者:Jia-fei Poon、Jiajie Yan、Vijay P. Singh、Paul J. Gates、Lars Engman
DOI:10.1002/chem.201602377
日期:2016.8.26
The synthesis of a variety of aromatic amines carrying an ortho‐alkyltelluro group is described. The new antioxidants quenched lipidperoxyl radicals much more efficiently than α‐tocopherol and were regenerable by aqueous‐phase N‐acetylcysteine in a two‐phase peroxidation system. The inhibition time for diaryl amine 9 b was four‐fold longer than recorded with α‐tocopherol. Thiol consumption in the aqueous