Novel Synthetic Approaches for the Tandem Cyclization of 1,6‐Enynes

Within the realm of organic compounds, carbocycles, heterocycles, bridged rings, and fuzed rings serve as core structural scaffolds for numerous bioactive molecules and functional materials. These cyclic motifs typically bear one or more stereocenters and are pervasively present in pharmaceutical agents, agrochemicals, and advanced functional materials. Their unique structural and physicochemical properties have rendered the efficient, selective construction of these cyclic scaffolds an important research direction in the field of organic synthesis. Among the most synthetically valuable transformations with profound research and application potential, the cascade reaction of 1,6‐enynes aligns perfectly with these core objectives. This transformation integrates multiple discrete reaction steps into a single one‐pot process, enabling the precise, controllable, and efficient construction of target molecules from simple, readily available starting materials. In recent years, the cascade cyclization of 1,6‐enynes has garnered considerable attention from research groups worldwide, particularly in the construction of fuzed cyclic frameworks including [6/6], [6/5], [6/6/5], and [6/5/5] systems. A succession of seminal research findings has been published in this area, facilitating the development of diverse synthetic strategies characterized by high efficiency and precise selectivity. Against this backdrop, the present review systematically summarizes the latest research advances in 1,6‐enyne cascade cyclization reactions, with the relevant research categorized into four main sections: (1) Visible light‐mediated 1,6‐enyne cascade cyclization reactions; (2) Metal‐free‐catalyzed 1,6‐enyne cascade cyclization reactions; (3) Transition metal‐catalyzed 1,6‐enyne cascade cyclization reactions; (4) Electrocatalytic 1,6‐enyne cascade cyclization reactions.