Su Miao-Dong, Liu Hai-Ping, Cao Zhong-Zhong, Liu Yufeng, Li Hui, Nie Zhi-Wen, Yang Tong-Lin, Luo Wei-Ping, Liu Qiang, Guo Can-Cheng
College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha 410082, China.
J Org Chem. 2021 Oct 1;86(19):13446-13453. doi: 10.1021/acs.joc.1c01550. Epub 2021 Sep 21.
Two C═C bond participation in annulation to pyridines using ,-dimethylformamide (DMF) as the N1 and C4 synthons has been carried out. In this reaction, DMF contributed one N atom and one C atom to two disconnected positions of pyridine ring, with no need for an additional nitrogen source. Two C═C bonds in two molecules of substituted styrenes offered four carbon atoms in the presence of iodine and persulfate. With the optimized conditions in hand, both symmetric and unsymmetric diaryl-substituted pyridines were obtained in useful yields. On the basis of relevant literature and a series of control experimental results, a possible mechanism was proposed in this work, which may demonstrate how DMF provides both N1 and C4 sources.
利用N，N-二甲基甲酰胺（DMF）作为N1和C4合成子，实现了两个碳碳双键参与构建吡啶环的环化反应。在该反应中，DMF为吡啶环的两个不相连位置提供了一个氮原子和一个碳原子，无需额外的氮源。在碘和过硫酸盐存在下，两个取代苯乙烯分子中的两个碳碳双键提供了四个碳原子。基于优化的条件，对称和不对称二芳基取代的吡啶均以可观的产率得到。根据相关文献和一系列对照实验结果，本工作提出了一种可能的机理，该机理或许能说明DMF如何同时提供N1和C4源。
