Efficient Aryl-(Hetero)Aryl Coupling by Activation of C-Cl and C-F Bonds Using Nickel Complexes of Air-Stable Phosphine Oxides

摘要

Transition-metal-catalyzed cross-coupling reactions of orga-nomagnesium compounds are useful tools for the synthesis of unsymmetrically substituted biaryls,which are valuable building blocks for the synthesis of natural products,liquid crystals,polymers,and ligands.Predominantly aryl iodides and bromides,and more recently aryl chlorides,are employed as electrophiles.In contrast,the catalytic activation of unreactive C-F bonds remains extremely challenging because of the inherent strength of the C-F bond.The activation of C-F bonds in general is of utmost importance because this transformation contributes to the fundamental understanding of the reactivity of very stable bonds,and because the selective synthesis of partially fluorinated compounds is still a challenge.