School of Chemical Engineering , Yeungnam University , Gyeongsan 38541 , Republic of Korea.
Graduate School of Pharmaceutical Sciences , The University of Tokushima , 1-78-1 Shomachi , Tokushima 770-8505 , Japan.
Org Lett. 2018 Sep 21;20(18):5648-5652. doi: 10.1021/acs.orglett.8b02363. Epub 2018 Sep 4.
An efficient synthesis of highly π-extended carbazoles is described via an unexpected domino [5 + 3 + 1] annulation approach. The Cu(I)-/base-promoted reactions of 2-nitrocinnamaldehydes with benzyl cyanides provide diverse benzo[ b]carbazoles. The reaction is proposed to proceed via a sequential Michael addition/intramolecular addition of an enol into a nitro group, 6π- electrocyclization, and the final oxidative aromatization as supported by density functional theory calculations. Some of the synthesized carbazoles showed significant potential in fluorescence sensing of Cu ions.
描述了一种通过出乎意料的多米诺 [5 + 3 + 1] 环化方法高效合成高度π-扩展咔唑的方法。Cu(I)/碱促进的 2-硝基亚肉桂醛与苄基氰化物的反应提供了多种苯并[b]咔唑。该反应被认为是通过迈克尔加成/烯醇与硝基的分子内加成、6π-电环化和最终的氧化芳构化的顺序进行的，这得到了密度泛函理论计算的支持。一些合成的咔唑在铜离子的荧光传感中显示出了显著的潜力。
