(NHC)Cu-Catalyzed Mild C–H Amidation of (Hetero)arenes with Deprotectable Carbamates: Scope and Mechanistic Studies

Primary arylamines are an important unit broadly found in synthetic, biological, and materials science. Herein we describe the development of a (NHC)Cu system that mediates a direct C–H amidation of (hetero)­arenes by using N-chlorocarbamates or their sodio derivatives as the practical amino sources. A facile stoichiometric reaction of reactive copper-aryl intermediates with the amidating reagent led us to isolate key copper arylcarbamate species with the formation of a C–N bond. The use of tBuONa base made this transformation catalytic under mild conditions. The present (NHC)­Cu-catalyzed C–H amidation works efficiently and selectively on a large scale over a range of arenes including polyfluorobenzenes, azoles, and quinoline N-oxides. Deprotection of the newly installed carbamate groups such as Boc and Cbz was readily performed to afford the corresponding primary arylamines.伯芳胺（Primary arylamines）是一类重要的结构单元，广泛存在于合成科学、生物科学与材料科学领域。本文报道了一种氮杂环卡宾铜（(NHC)Cu）催化体系的开发，该体系可采用N-氯代氨基甲酸酯或其钠盐衍生物作为实用氨基源，实现（杂）芳烃的直接C-H酰胺化反应。通过活性芳基铜中间体与酰胺化试剂的便捷计量反应，我们分离得到了关键的芳基氨基甲酸铜物种，并伴随C-N键的生成。使用叔丁醇钠（tBuONa）作为碱，该转化反应可在温和条件下实现催化循环。本(NHC)Cu催化的C-H酰胺化反应对多种芳烃底物（包括多氟苯、唑类及喹啉N-氧化物）均表现出高效且高选择性的催化性能，且可实现规模化应用。对新引入的氨基甲酸酯保护基（如叔丁氧羰基（Boc）和苄氧羰基（Cbz））进行简便脱保护，即可得到对应的伯芳胺产物。