Efficient Aqueous-Phase Heck and Suzuki Couplings of Aryl Bromides Using Tri(4,6-dimethyl-3- sulfonatophenyl)phosphine Trisodium Salt (TXPTS)
Lucas R. Moore and Kevin H. Shaughnessy*
*Department of Chemistry and the Center for Green Manufacturing, The
University of Alabama, Tuscaloosa, Alabama 35487-0336, Email:
kshaughn
bama.ua.edu
L. R. Moore, K. H. Shaughnessy, Org. Lett., 2004, 6, 225-228.
DOI: 10.1021/ol0360288
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Abstract
Sterically demanding, sulfonated arylphosphine ligands have been applied to the aqueous-phase Heck and Suzuki coupling of aryl bromides. TXPTS promotes the aqueous-phase Heck coupling under mild conditions and provides good yields of coupling products from aryl bromides at 80°C. Active catalysts for Suzuki couplings of aryl bromides at 50°C and 80°C are described.
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Details
The document discusses the use of sterically demanding, sulfonated arylphosphines TXPTS and TMAPTS in aqueous-phase Heck and Suzuki couplings of aryl bromides. TXPTS, in combination with palladium acetate, provides good yields of Heck coupling products at 80 °C, outperforming TMAPTS and TPPTS. TXPTS is notable for promoting Heck couplings under mild conditions, a first for unactivated aryl bromides below 100 °C. Both TXPTS and TMAPTS are effective in Suzuki couplings at 50 °C, with TXPTS showing higher activity. The study highlights water as an attractive solvent due to its low cost, toxicity, and environmental impact, and the potential for recycling water-soluble catalysts. The research aims to identify more efficient ligands for aqueous-phase cross-coupling reactions, focusing on modifying the steric and electronic properties of water-soluble arylphosphines. The document concludes that TXPTS provides significant advantages in Heck couplings and moderate improvements in Suzuki couplings, offering a practical and environmentally friendly approach to these reactions. The work was supported by the National Science Foundation and The University of Alabama.
Key Words
Heck Reaction, Suzuki Coupling, Green Chemistry
ID: J54-Y2004-060
