Nickel-catalysed substitutions of aryl tert-butyl sulfones with organometallic reagents: Synthesis of ortho-substituted unsymmetrical biaryls

In the presence of a catalytic amount of a nickel salt, aryl tert-butyl sulfones react with aryl Grignard reagents to give biaryls. This reaction is used in conjunction with the powerful ortho-lithiation-directing ability of aryl tert-butyl sulfonyl groups to make unsymmetrical ortho-substituted biaryls. In certain cases, the substitution of an aryl alkylsulfonyl group by an organometallic reagent is possible without a transition metal catalyst.