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Synlett 2006(12): 1891-1894  
DOI: 10.1055/s-2006-948163
LETTER
© Georg Thieme Verlag Stuttgart · New York

Desulfitative Suzuki Cross-Couplings of Arylsulfonyl Chlorides and Boronic Acids Catalyzed by a Recyclable Polymer-Supported N-Heterocyclic Carbene-Palladium Complex Catalyst

Sujuan Zhang, Xiaoming Zeng, Zhijun Wei, Dongbing Zhao, Tairan Kang, Weifeng Zhang, Mei Yan, Meiming Luo*
Key Laboratory of Green Chemistry & Technology of Ministry of Education at Sichuan University, College of Chemistry, Sichuan ­University, Chengdu 610064, P. R. of China
Fax: +86(28)85462021; e-Mail: luomm@scu.edu.cn;
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Publikationsverlauf

Received 15 March 2006
Publikationsdatum:
24. Juli 2006 (online)

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Abstract

An effective and easy-to-handle process for the desulfitative Suzuki cross-couplings of arylsulfonyl chlorides and boronic acids in the presence of a recyclable polymer-supported NHC-Pd complex was developed. The supported catalyst could be reused several times with little loss of catalytic activity.

Key words

Suzuki reaction - N-heterocyclic carbene-palladium complex - polymer-supported catalysts - recyclable catalysts - aryl­sulfonyl chlorides

11

General Procedure for the Suzuki Cross-Couplings of Arylsulfonyl Chlorides and Arylboronic Acids Catalyzed by the Polymer-Supported NHC-Pd Catalyst. A 25 mL, round-bottom flask equipped with a magnetic stirring bar and a reflux condenser was charged with arylboronic acid (2 mmol), arylsulfonyl chloride (0.5 mmol), Na2CO3 (1.5 mmol) and the polymer-supported NHC-Pd catalyst 1 (125 mg, 12.5 µmol Pd). The flask was connected to a vacuum line and then filled with argon (three times) before 5 mL THF was added. The resulting mixture was stirred and heated to reflux. After cooling to ambient temperature, the catalyst was filtered and washed with THF (3 × 4 mL), and then dried in vacuum for use in next run. The combined organic phase was dried over anhydrous MgSO4, filtered and evaporated under reduced pressure. The product was purified by column chromatography.
2,5-Dichlorobiphenyl: colorless oil. 1H NMR (400 MHz, CDCl3): δ = 7.23-7.28 (m, 1 H), 7.34 (d, J = 2.4 Hz, 1 H), 7.37-7.47 (m, 6 H). 13C NMR (100 MHz, CDCl3): δ = 141.9, 138.1, 132.5, 131.1, 131.0, 130.8, 130.6, 129.6, 129.2, 126.4, 126.2, 126.1. MS (EI): m/z (%) = 222 (100) [M+], 186 (7), 152 (49).
Other cross-coupling products were identified by comparing their NMR spectra and melting points with those reported in the literature.