Synthesis of Biaryls and Polyaryls by Ligand-Free Suzuki Reaction in Aqueous Phase

Abstract

A highly efficient palladium acetate-catalyzed ligand-free Suzuki reaction in aqueous phase was developed in short reaction times (0.5-1 h) at 35 degrees C in air. The key for such a successful catalytic system was the use of a suitable amount of cosolvents in the aqueous phase. The method could be extended to the consecutive multi-Suzuki coupling, and polyaryls were prepared in a single one-pot step in high selectivity and excellent yield under mild reaction conditions (60 degrees C).

Mild and Ligand‐Free Palladium‐Catalyzed Cross‐Couplings between Aryl Halides and Arylboronic Acids for the Synthesis of Biaryls and Heterocycle‐Containing Biaryls

“…Impressive progress in the development of efficient catalytic systems to achieve this reaction under mild conditions has been made in the last several years, [3,4] but there still exists considerable room for further exploration, as only a few methods for palladiumcatalyzed Suzuki-Miyaura coupling at room temperature without the aid of any ligands have been developed. [5][6][7] Among those ligand-free and room temperature SuzukiMiyaura coupling transformations, many methods have still required other additional promoters, [5] such as phase-trans-perature in EtOH as the solvent. Moreover, the Pd(OAc) 2 / MeONa catalytic system could also be applied in couplings between heteroaryl halides and arylboronic acids to provide satisfactory results in MeOH as the solvent after prolonged reaction times.…”

One-Pot Homo- and Cross-Coupling Reactions of Arenediazonium Tosylate Salts for the Synthesis of Biaryls and Polyaryls

“…Recent reports concerning the palladium catalyzed synthesis of biaryls [26][27][28] prompted our design of a scheme that combines homo-and cross-coupling reactions (Scheme 1) of arenediazonium tosylate salts for a short and efficient synthetic route to polyaryls. We began our study with the homo-coupling reaction of arenediazonium tosylate and bisulfate salts.…”

Recent Strategies in Organic Reactions Catalyzed by Phase Transfer Catalysts and Analyzed by Gas Chromatography

“…In recent times, there has been great interest in developing green chemical reactions that make carbon-carbon bonds using water as a solvent and applying these reactions in academic and industrial lab settings (Deveau & Macdonald, 2004;Li, 2005;Liu, et al, 2006). Hence researchers started do deal with the coupling reaction in aqueous two-phase systems (Genet et al, 1995) with water-soluble palladium complexes as catalysts allowing easy separation of the water phase which contains the palladium catalyst and a strong base to bind the formed hydrogen halide.…”