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Synlett 2011(5): 702-706  
DOI: 10.1055/s-0030-1259542
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Efficient Copper-Catalyzed Sonogashira Couplings of Aryl Halides with Terminal Alkynes in Water

Daoshan Yanga,, Bing Lia,, Haijun Yanga, Hua Fu*a, Liming Hu*b
a Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, P. R. of China
b College of Life Sciences and Bioengineering, Beijing University of Technology, Beijing 100124, P. R. of China
Fax: +86(10)62781695; e-Mail: fuhua@mail.tsinghua.edu.cn;
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Publication History

Received 21 October 2010
Publication Date:
08 February 2011 (online)

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Abstract

An efficient copper-catalyzed method has been developed for Sonogashira couplings of aryl halides with terminal alkynes in water. The protocol uses inexpensive CuBr as the catalyst, 1,10-phenanthroline as the ligand, tetrabutylammonium bromide (TBAB) as the phase-transfer catalyst, environmentally friendly water as the solvent, and various internal alkynes were synthesized in good to excellent yields.

Key words

copper - water - Sonogashira coupling - synthetic method - alkyne

1

These two authors contributed equally to this work.

18

General Procedure for the Synthesis of Compounds 3a-u A 10 mL Schlenk tube equipped with a magnetic stirring bar was charged with CuBr (0.1 mmol, 15 mg), NaOH (2 mmol, 80 mg), 1,10-phenanthroline (0.2 mmol, 36 mg), TBAB [0.2-1 mmol, see Table  [²] for the details; note: an additional KI (2 mmol) should be added for aryl bromide]. The tube was evacuated and back-filled with nitrogen, and this procedure was repeated three times. Aryl halide (1.0 mmol), alkyne (2 mmol), and H2O (1.5 mL) were sequentially added to the tube at r.t. under a stream of nitrogen, and the tube was sealed and put into a pre-heated oil bath at 120 ˚C for 24 h under nitrogen atmosphere. After the resulting solution was cooled to r.t., and the solution was extracted with EtOAc (3 × 3 mL). The combined organic phase was concentrated, and the remained residue was purified by column chroma-tography on silica gel to provide the desired product.