Ring Expansion Reactions through Intramolecular Transamidation

Abstract

Synthetic methodologies based on cycle expansion reactions have proven to be highly effective in delivering valuable medium‐sized cycles and macrocycles. A primary method of ring expansion relies on intramolecular transamidation reactions. These reactions typically employ N‐aminoalkyl and N‐aminoacyl derivatives of lactams and their analogues as starting materials, yielding a diverse spectrum of unique nitrogen‐containing heterocycles. This Review aims to provide a comprehensive analysis of the research outcomes related to intramolecular transamidation reactions that lead to cycle expansion. This will offer the reader a perspective on the potential applications of such reactions in generating novel and intriguing types of heterocyclic systems.

Medium-Sized Ring Expansion Strategies: Enhancing Small-Molecule Library Development

“…Thus, exploring new bioactive chemical spaces through medium-sized ring synthesis is essential for discovering novel bioactive compounds. Ring-expansion reactions of polycyclic substrates are key to synthesizing mediumsized rings, enabling the efficient and practical creation of various molecular structures that cannot be achieved through direct cyclization due to enthalpic and entropic factors [43][44][45][46][47]. This approach allows chemists to efficiently synthesize medium-sized rings, which are essential for drug development and the construction of medium-sized ringbased small-molecule libraries, by efficiently transforming smaller rings or linear precursors.…”