Cross-Coupling of Aryl Halides and Triflates with Intramolecularly Stabilized Group 13-Metal Alkylating Reagents in the Presence of Mixed-Metal Catalysts

In the presence of tertiary phosphines, the palladium-containing mixed-metal complexes [(CO) 4 Fe(μ-PPh 2 )Pd(μ-Cl)] 2 (1) and [(CO) 3 Co] 2 (μ-CO)Pd[μ-(Ph 2 PCH 2 ) 2 ] (2) catalyze the cross-coupling of aryl triflates and halides (including chlorides) with intramolecularly stabilized dialkylaluminum, -gallium and -indium reagents 3-8. The reactions are high yielding, and homocoupling and hydrodehalogenation processes are minimal even when the alkyl moieties of the alkylating reagents contain β-hydrogen atoms. As the components of the mixed-metal complexes are either poor catalysts, or completely inactive, the high catalytic activity of 1 and 2 is attributed to synergism between the different metal nuclei of the catalysts.