Synthesis of N‐heterocycles via [4 + 3] cycloaddition of azomethine imine

Abstract

Di, tri and tetra‐nitrogen containing 7‐membered heterocycles are the key building blocks for natural and medicinally active compounds. They are using as antidepressants, antiulcer, antibiotics, antiemetic and also used as herbicides and insecticides. These building blocks can be synthesized easily from [4 + 3] cycloadditon reaction of azomethine imine with the other suitable reacting partner. Research on this area is very much important as this area is not much explored till now. Hence, the synthetic literature survey towards the di‐nitrogen containing heterocycles is paramount importance. Herein, we report numerous synthetic routes (metal catalyzed, metal free, asymmetric) of di‐nitrogen containing 7‐membered heterocycle through [4 + 3] cycloadditon reaction of the last 10 years (2011‐2019).