An efficient catalyst for the synthesis of ortho-substituted biaryls by the Suzuki cross-coupling: Triphenylphosphine adduct of cyclopalladated ferrocenylimine

The air and moisture stable triphenylphosphine adduct of cyclopalladated ferrocenylimine 2 has been successfully used in palladium-catalyzed Suzuki cross-coupling for the synthesis of ortho-substituted biaryls in air. In the presence of 0.05 mol% of 2 as catalyst and 3 equivalent of CsF as base in dioxane at 100 °C, ortho-substituted biaryls were synthesized with moderate to high yields in the reactions of 2-methoxy-1-naphthylboronic acid with aryl halides, and 14 new ortho-substituted biaryls were obtained and characterized.