Palladium-complexes (Pd0) are extensively utilized to construct carbon-carbon (C-C) bonds via cross-coupling of organohalides with organometallic reagents. In sharp contrast, applications of the isoelectronic CuI complexes to conduct similar transformations are quite rare. We now demonstrate that a bidentate PN-ligand coordinates to CuX (X = halides, OMe) to generate a catalytically active (PN)CuX complex that enables the cross-couplings of organohalides to proceed efficiently with a variety of organometallic coupling partners. Preliminary mechanistic investigations by synthesizing and characterizing various potential reaction intermediates, studying their reactivity with organohalides and radical probes, and monitoring the progress of stepwise stoichiometric reactions in situ by 1H, 19F, 11B and 31P NMR spectroscopies indicate that these transformations proceed via a CuI/CuIII or CuI/CuII redox cycle that involves initial transmetalation followed by reaction with organohalides, the reverse order of elementary steps known for Pd-catalysis.

Copper-catalyzed cross-couplings for carbon-carbon bond formation

248th National Meeting (2014)

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