Skeletal Editing via Transition‐Metal‐Catalyzed Nitrene Insertion

Metal‐nitrenes are valuable reactive intermediates for synthesis and are widely used to construct biologically relevant scaffolds, complexes and functionalized molecules. The ring expansion of cyclic molecules via single‐nitrogen‐atom insertion via nitrene or metal‐nitrenoid intermediates has emerged as a promising modern strategy for driving advantageous nitrogen‐rich compound synthesis. In recent years, the catalytic insertion of a single nitrogen atom into carbocycles, leading to N‐heterocycles, has become an important focus of modern synthetic approaches with applications in medicinal chemistry, materials science, and industry. Catalytic single‐nitrogen‐atom insertions have been increasing in prominence in modern organic synthesis due to their capability to construct high‐value added nitrogen‐containing heterocycles from simple feedstocks. In this review, we will discuss the rapidly growing field of skeletal editing via single‐nitrogen‐atom insertion using transition metal catalysis to access nitrogen‐containing heterocycles, with a focus on nitrogen insertion across a wide spectrum of carbocycles. Nitrene is a highly reactive species that is commonly employed in a single‐nitrogen‐atom insertion reaction and skeletal editing for generating N‐heterocycles. Skeletal editing with reactive via nitrogen insertion has recently emerged as a powerful strategy in modern synthesis. In this review, we address the rapidly expanding field of nitrene insertion, which includes skeletal editing and nitrogen atom insertion, the use of various nitrogen sources to access nitrogen‐containing heterocycles, and our present understanding of the process.