Synlett 2005(11): 1671-1674  
DOI: 10.1055/s-2005-869877
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© Georg Thieme Verlag Stuttgart · New York

Suzuki-Miyaura Cross-Coupling of Aryl Chlorides in Water Using Ligandless Palladium on Activated Carbon

Morten Lysén*a,b, Klaus Köhlera
a Department Chemie, Anorganische Chemie, TU München, Lichtenbergstr. 4, 85747 Garching, Germany
b The Danish University of Pharmaceutical Sciences, Universitetsparken 2, 2100 Copenhagen, Denmark
Fax: +45(35)306040; e-Mail: mly@dfuni.dk;
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Publikationsverlauf

Received 1 April 2005
Publikationsdatum:
09. Juni 2005 (online)

Abstract

Aqueous reaction conditions that activate various aryl chlorides in Suzuki-Miyaura cross-coupling have been developed. These environment friendly conditions utilize ligandless Pd/C (Pd concentrations 0.2-2 mol%) that allow easy separation of the catalyst at the end of the reaction.

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Representative Procedure.
A pressure tube was charged with Pd/C (0.2 mol%; commercially available E105CA/W 5% Pd, product of Degussa AG, or self-prepared [14] ), TBAB (2 mmol), NaOH (10 mmol), phenylboronic acid (4.4 mmol) and 4-chloro-acetophenone (4 mmol). Then, H2O (6 mL) was added and the flask was sealed with a Teflon screw cap and stirred at 100 °C for 2 h. After cooling to r.t., CH2Cl2 (15 mL) was added and the reaction was filtered through a plug of celite to remove the catalyst. The filter was flushed with CH2Cl2 (2 × 15 mL) and the combined organic phase was dried (MgSO4), evaporated on Celite and purified by flash chromatography to yield 1-biphenyl-4-yl-ethanone (entry 2a, 776 mg, ca. 99%).