BF·OEt-catalyzed/mediated alkyne cyclization: a comprehensive review of heterocycle synthesis with mechanistic insights.

The quest for efficient and versatile methods for heterocycle synthesis continues to drive innovation in organic chemistry. In this context, the cyclization of alkynes catalyzed or mediated by boron trifluoride diethyl etherate (BF·OEt) has emerged as a powerful and widely applicable strategy. This review provides a comprehensive and authoritative overview of BF·OEt-catalyzed/mediated alkyne cyclization reactions, covering the scope, mechanisms, and applications of these processes. We discuss the synthesis of a diverse range of heterocyclic compounds, including dihydropyrans, quinolines, dehydropiperidines, oxindoles and others, and highlight the unique advantages of BF·OEt as a catalyst/mediator. Recent advances, challenges, and future directions in this rapidly evolving field are also addressed. This review aims to serve as a valuable resource for synthetic chemists, inspiring further research and applications in this exciting area.