College of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China.
College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China.
Org Biomol Chem. 2022 Sep 28;20(37):7391-7404. doi: 10.1039/d2ob01344d.
In recent years, many methods for the facile synthesis of pyridines and their derivatives have been developed. The [2 + 2 + 2] cycloaddition reaction of alkynes and nitriles catalyzed by transition metals has emerged as the most straightforward and efficient method to obtain pyridine derivatives. Recently, Earth-abundant cobalt has been employed as a versatile and economical catalyst for the synthesis of functionalized molecules, as compared to other transition metals. This review mainly focuses on the recent research and development of the Co-catalyzed intramolecular [2 + 2 + 2] cycloaddition of diynes-nitriles or intermolecular [2 + 2 + 2] cycloaddition reaction of alkynes or diynes with nitriles for the construction of chiral or achiral multi-substituted pyridines. Meanwhile, brief mechanistic insights are also discussed here to explain the observed regioselectivity.
近年来，已经开发出许多简便合成吡啶及其衍生物的方法。炔烃和腈的[2 + 2 + 2]环加成反应在过渡金属的催化作用下已成为获得吡啶衍生物最直接、最有效的方法。最近，与其他过渡金属相比，丰富的地球元素钴已被用作合成功能分子的通用且经济的催化剂。本文主要综述了近年来钴催化的二炔-腈分子内环[2 + 2 + 2]加成或炔烃或二炔与腈的分子间[2 + 2 + 2]环加成反应构建手性或非手性多取代吡啶的研究进展。同时，本文还讨论了简要的反应机理，以解释观察到的区域选择性。
