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Published on: February 16, 2020
Regioselective Reductive Coupling of o-Haloaromatic Ketones with Terminal Alkynes via Photoredox/Cobalt Dual
Gui-Fen Qian1, Ruo-Ping Zheng1, Ting-Ting Miao1
1College of Chemistry and Chemical Engineering, and Key (Guangdong-Hong Kong Joint) Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University, Shantou 515063, P. R. China.
Abstract:
The regioselective reductive coupling of o-haloaromatic ketones with alkynes to access indenols still poses a challenge, as existing methods typically rely on stoichiometric metal reductants and elevated temperatures. Herein, we describe a photoredox/cobalt catalytic system that enables selective reductive coupling of o-iodo, o-bromo, and o-chloroaromatic ketones as well as o-bromoaromatic aldehydes, with terminal alkynes to afford 2-substituted indenols. This protocol uses a tertiary amine as the terminal reductant, proceeds at room temperature, and features mild conditions, excellent regioselectivity, and broad substrate scope.
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