Rhodium(II)-Catalyzed Regioselective Remote C–H Alkylation of Protic Indoles

作者：Lingheng Kong, Han Xi, Haohua Chen, Huaming Sun, Yu Lan, Xingwei Li · 发表于：ACS Catalysis · 年份：2021 · DOI：10.1021/acscatal.1c01052 · 被引用次数：40 · 研究领域：Catalytic C–H Functionalization Methods、Cyclopropane Reaction Mechanisms、Catalytic Cross-Coupling Reactions

Control of regioselectivity that defies the intrinsic reactivity of arene C–H bonds remains a formidable challenge. In this work, dimeric Rh(II) complexes have been applied as an efficient catalyst for the regioselective coupling of NH indoles with diazo compounds. Two-substituted indoles mostly reacted with C(6) selectivity. Mechanistic studies revealed that the regioselectivity results from the hydrogen-bonding directing effect, and the C–C bond formation proceeds via the Friedel–Crafts-type attack of indole toward the Rh(II) carbene species. In contrast, the reaction of 4-methoxyindoles occurred exclusively with the complementary C(7) selectivity.