Organocatalytic oxidative dehydrogenation of aromatic amines for the preparation of azobenzenes under mild conditions
作者:Hengchang Ma、Wenfeng Li、Jian Wang、Guanghai Xiao、Yuan Gong、Chunxuan Qi、Yunpeng Feng、Xiufang Li、Zhikang Bao、Wei Cao、Qiangsheng Sun、Caraus Veaceslav、Feng Wang、Ziqiang Lei
DOI:10.1016/j.tet.2012.07.012
日期:2012.9
(Diacetoxyiodo)benzene used as stoichiometrically and catalytically in the preparation of azobenzenes under mild reaction conditions was developed. The metal-free oxidation systems demonstrated wide substituents tolerance, alkyls, halogens, and several versatile functional groups, such as amino, ethynyl, and carboxyl substituents are compatible well, and the corresponding products could be formed with good to excellent yields. In this disclosed method, the more large scale formation of azo compounds also could be carried out successfully. Of note that 3-ethynylbenzenamine applied as a very useful cross dehydrogenative partner, which coupled with different anilines, providing asymmetrical azo compounds with acceptable yields in one step under very mild reaction conditions. (C) 2012 Elsevier Ltd. All rights reserved.
Diacetoxyiodo 苯用于在温和条件下作为计量和催化试剂制备 azobenzene,这一方法得到了发展。该无金属氧化体系对各种取代基表现出广泛的容受度,包括烷基、卤素以及多种多样的功能基团,例如氨基、炔基和羧酸基,这些基团的反应配合良好,所得产物具有良好的收率到 excellent收率。在所披露的方法中,还能够成功地实现大规模 azo 化合物的形成。值得注意的是,3-ethynylbenzenamine可作为非常有用的交叉脱氢配位剂,与各种苯胺类物质融合作为伴侣,可在极其温和的反应条件下一步合成不对称 azo 化合物,且产率良好。 (C) 2012 Elsevier Ltd. All rights reserved.