A Simple and Highly Efficient Catalytic System for Suzuki Cross-Coupling Using Ligandless Palladium Chloride

Xiaochun Tao; Yinyan Zhao; Dong Shen

doi:10.1055/s-2003-44992

LETTER

A Simple and Highly Efficient Catalytic System for Suzuki Cross-Coupling Using Ligandless Palladium Chloride

Xiaochun Tao^a, Yinyan Zhao^a, Dong Shen*^b
^a Laboratory of Organometallic Chemistry, East China University of Science and Technology, Shanghai 200237, P. R. China
^b Laboratory of Chemical Physics, East China University of Science and Technology, Shanghai 200237, P. R. China
e-Mail: shen@ecust.edu.cn;

Abstract

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Abstract

Ligandless palladium chloride catalyzed Suzuki cross-coupling reaction of a series of aryl bromides and arylboronic acids in pyridine, with K₂CO₃ as the base, afforded the corresponding biaryls in surprisingly high yields. The quantities of PdCl₂ employed were especially low (0.2-0.3 mol%) and the solvent pyridine could be recovered in high amounts (>90%).

Key words

ligandless - palladium chloride - Suzuki cross-coupling - aryl bromide - arylboronic acid

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References

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7

General Procedure: A Schlenk tube was charged with aryl bromide (2.0 mmol), arylboronic acid (3.0 mmol), K₂CO₃ (4.0 mmol), PdCl₂ (0.3 mol%) and pyridine (3 mL). The Schlenk tube was then put under an atmosphere of Ar and placed in an oil bath and heated to the reflux. Upon complete consumption of the aryl bromides as determined by TLC analysis, the reaction mixture was allowed to cool down to r.t. and the solvent was recovered under vacuum (volume recovered was greater than 2.7 mL). The remains were isolated by column chromatography. All biaryl products were characterized by melting points and ¹H NMR spectra.