Cu(II)/Base\nSynergistic Promoted [2 + 1 + 3] Cyclization\nof Cyclic Ketones with α,β-Unsaturated Aldehydes/Ketones\nand NH<sub>4</sub>I to Access Fused Pyridines

Herein,\na practical three-component [2 + 1 + 3] cyclization of\nvarious cyclic ketones with α,β-unsaturated aldehydes/ketones\nand ammonium iodide (NH<sub>4</sub>I) to access highly functional\nfused pyridines has been developed. The features of this transformation\ninclude mild reaction conditions, readily available starting materials,\nand excellent chemoselectivity. This protocol is compatible with various\nfunctional groups, and the preliminary studies on the mechanism of\nthe reaction are also provided.