Superb efficient and recycle polymer-anchored systems for palladium catalyzed Suzuki cross-coupling reactions in water

A set of three new polymer-anchored palladium(II) Schiff base catalysts have been synthesized, characterized and their catalytic activity was investigated in the Suzuki cross-coupling reaction between aryl halides and arylboronic acid in the presence of Cs2CO3 as a base. They show excellent catalytic activity in coupling of aryl bromides or aryl iodide with phenylboronic acid under the optimized reaction conditions in water. Polymer–anchored Pd(II) complexes provided turnover frequency of 29,700 or 58,200 h−1 in Suzuki coupling reactions of phenylboronic acid with p-bromoacetophenone or p-iodobenzene, respectively, which are the highest values ever reported for the Suzuki coupling reactions in water as sole solvent. The catalyst 1 could be used for 15 reaction cycles in the Suzuki coupling of p-acetobromobenzene at 100 °C with no loss of catalytic activity.

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► Three new polymer-anchored palladium(II) Schiff base catalysts were synthesized.
► Their catalytic activity was investigated in the Suzuki cross-coupling reaction.
► They provided biphenyls in water with the highest TOF values ever reported.