Copper-catalyzed C(sp)–H aryl amination enables modular synthesis of quinolines and 2-quinolinones

Herein, we disclose a novel copper-catalyzed C(sp)–H aryl amination of terminal alkynes with anthranils, enabling the rapid generation of highly reactive secondary N-aryl ynamines for the modular synthesis of structurally diverse C2-substituted quinolines and 2-quinolinones. The in-situ formed carbonyl-ynamines are prone to tautomerize to carbonyl-ketenimines, which can efficiently react with a series of nucleophiles, including amines, alcohols, phenols, thiols, thiophenols, active-methylene compounds, and even water to produce various quinoline derivatives with the generation of H₂O as a sole and green byproduct. This method also unlocks a practical route to create various quinoline-fused heterocycles and can be successfully applied to the late-stage modification of complex molecules and the concise synthesis of bioactive targets. Mechanistic studies reveal a copper-catalyzed inner-sphere nitrene transfer process by using anthranils as novel aryl nitrene precursors.