Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87185, USA.
Molecules. 2020 Dec 15;25(24):5950. doi: 10.3390/molecules25245950.
Pyrazole, a member of the structural class of azoles, exhibits molecular properties of interest in pharmaceuticals and materials chemistry, owing to the two adjacent nitrogen atoms in the five-membered ring system. The weakly basic nitrogen atoms of deprotonated pyrazoles have been applied in coordination chemistry, particularly to access coordination polymers and metal-organic frameworks, and homocoupling reactions can in principle provide facile access to bipyrazole ligands. In this context, we summarize recent advances in homocoupling reactions of pyrazoles and other types of azoles (imidazoles, triazoles and tetrazoles) to highlight the utility of homocoupling reactions in synthesizing symmetric bi-heteroaryl systems compared with traditional synthesis. Metal-free reactions and transition-metal catalyzed homocoupling reactions are discussed with reaction mechanisms in detail.
吡唑是唑类结构单元中的一员，由于其五元环系统中相邻的两个氮原子，吡唑具有在药物和材料化学方面的分子特性。去质子化吡唑的弱碱性氮原子已应用于配位化学，特别是用于获得配位聚合物和金属有机骨架，并且偶联反应原则上可以很容易地获得双吡唑配体。在这种情况下，我们总结了吡唑和其他类型的唑（咪唑、三唑和四唑）的偶联反应的最新进展，以突出偶联反应在合成对称双杂芳基系统方面与传统合成相比的优势。本文详细讨论了无金属反应和过渡金属催化的偶联反应及其反应机理。
