Iodine-catalyzed synthesis of <i>N</i>,<i>N</i>′-diaryl-<i>o</i>-phenylenediamines from cyclohexanones and anilines using DMSO and O<sub>2</sub> as oxidants
作者:Mingteng Xiong、Zhan Gao、Xiao Liang、Pengfei Cai、Heping Zhu、Yuanjiang Pan
DOI:10.1039/c8cc05320k
日期:——
A novel I2-catalyzed cross-dehydrogenative aromatization of cyclohexanones and anilines to synthesize N,N′-diaryl-o-phenylenediamines has been unprecedentedly developed with dimethyl sulfoxide and oxygen employed as mild terminal oxidants. To prove the rationality of the two separate dehydration steps of the proposed mechanism, a resulting I2-catalyzed cross-dehydrogenative aromatization of cyclohexenones
novel acid/base‐co‐catalyzeddirect intermolecular α‐amination of various cyclic ketones has been developed for the first time. The reaction employs molecular oxygen as the sole oxidant under metal‐free conditions. The reaction tolerates a wide range of various anilines, especially primary diamine derivatives, and provides a simple and efficient method for the constructions of α‐amino enones and benzodiazepine
Can Primary Arylamines Form Enamine? Evidence, α-Enaminone, and [3+3] Cycloaddition Reaction
作者:E. H. Nisala Fernando、Jose Cortes Vazquez、Jacqkis Davis、Weiwei Luo、Vladimir N. Nesterov、Hong Wang
DOI:10.1021/acs.joc.1c01462
日期:2021.11.5
α-enaminone formation suggests that an amine radical cation generated through O2 singlet energy transfer was involved in initiating α-enaminone formation. The reactivity and utility of α-enaminones were explored with a [3+3] cycloaddition reaction of enones affording dihydropyridines in good yields (58–85%). α-Enaminones displayed a set of reactivities that is different from that of enamines. The knowledge
通过核磁共振光谱检测并证实了由伯芳基胺形成烯胺。发现自由基猝灭剂例如(2,2,6,6-四甲基哌啶-1-基)氧化基的存在对于检测烯胺形成是必不可少的。还开发了由伯芳基胺和酮直接合成 α-烯胺酮的方法。α-烯胺酮形成的机理研究表明,通过 O 2产生的胺自由基阳离子单线态能量转移参与了α-烯胺酮的形成。通过烯酮的 [3+3] 环加成反应探索了 α-烯胺酮的反应性和效用,以良好的产率 (58-85%) 提供二氢吡啶。α-烯胺酮表现出一组不同于烯胺的反应性。在这项工作中获得的知识提高了我们对有机化学的基本理解,为烯胺催化提供了见解和新机会。
Formal oxo- and aza-[3 + 2] reactions of α-enaminones and quinones: a double divergent process and the roles of chiral phosphoric acid and molecular sieves
作者:Weiwei Luo、Zhicheng Sun、E. H. Nisala Fernando、Vladimir N. Nesterov、Thomas R. Cundari、Hong Wang
DOI:10.1039/d0sc02078h
日期:——
α-enaminones with quinones through facile manipulation of catalyst and additive, leading to structurally completely different products. The two divergent processes, which involve formal aza- and oxo-[3 + 2] cycloaddition reactions, are mediated by chiral phosphoricacid and molecular sieves, respectively. While inclusion of phosphoricacid in the reaction switched the reaction pathway to favor the
An efficient synthetic approach for the construction of the 1-oxygenated carbazole core is described. The condensation of cyclohexane-1,2-diones with a series of anilines yielded the corresponding 2-anilinocyclohex-2-en-1-ones, followed by the one-pot aromatization/methylation process of the latter to provide N-aryl-2-methoxyanilines. A palladium(II)-catalyzed cyclization of these N-aryl-2-methoxyanilines afforded the desired 1-methoxycarbazole frame in high overall yields. This protocol was implemented for the total synthesis of the naturally occurring glycozolicine and 6-methoxymurrayanine.