Nucleophilic Aryl Fluorination and Aryl Halide Exchange Mediated by a Cu I /Cu III Catalytic Cycle
2011; American Chemical Society; Volume: 133; Issue: 48 Linguagem: Inglês
10.1021/ja2058567
ISSN1943-2984
AutoresAlicia Casitas, Mercè Canta, Miquel Solà, Miguel Costas, Xavi Ribas,
Tópico(s)Catalytic C–H Functionalization Methods
ResumoCopper-catalyzed halide exchange reactions under very mild reaction conditions are described for the first time using a family of model aryl halide substrates. All combinations of halide exchange (I, Br, Cl, F) are observed using catalytic amounts of Cu(I). Strikingly, quantitative fluorination of aryl-X substrates is also achieved catalytically at room temperature, using common F(-) sources, via the intermediacy of aryl-Cu(III)-X species. Experimental and computational data support a redox Cu(I)/Cu(III) catalytic cycle involving aryl-X oxidative addition at the Cu(I) center, followed by halide exchange and reductive elimination steps. Additionally, defluorination of the aryl-F model system can be also achieved with Cu(I) at room temperature operating under a Cu(I)/Cu(III) redox pair.
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