The Suzuki Reaction in Aqueous Media Promoted by P, N Ligands

Molecules

Jason A. Weeden¹  Rongcai Huang¹  Kathryn D. Galloway¹  Phillip W. Gingrich¹ 

[1] Department of Chemistry, University of Nevada, Reno NV 89557, USA

关键词: C–C coupling;    aqueous phase Suzuki reaction;    1;    3;    5-triaza-7-phosphaadamantante (PTA);    water-soluble phosphine ligands;   

DOI  :  10.3390/molecules16086215

来源: mdpi

【 摘 要 】

The synthesis and structure of palladium complexes of trisubstituted PTA derivatives, PTA_R3, are described. Water-soluble phosphine ligands 1,3,5-triaza-7-phosphaadmantane (PTA), tris(aminomethyl)phosphine trihydrobromide, tri(aminomethyl) phosphine, 3,7-dimethyl-1,5,7-triaza-3-phosphabicyclo[3,3,1]nonane (RO-PTA), 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane (DAPTA), lithium 1,3,5-triaza-7-phosphaadamantane-6-carboxylate (PTA-CO₂Li), 2,4,6-triphenyl-1,3,5-triaza-7-phosphatricyclo [3.3.1.1]decane, and 2,4,6-triphenyl-1,3,5-triaza-7-phosphatricyclo[3.3.1.1]decane were used as ligands for palladium catalyzed Suzuki reactions in aqueous media. RO-PTA in combination with palladium acetate or palladium chloride was the most active catalyst for Suzuki cross coupling of aryl bromides and phenylboronic acid at 80 °C in 1:1 water:acetonitrile. The activity of Pd(II) complexes of RO-PTA is comparable to PPh₂(m-C₆H₄SO₃Na) (TPPMS) and P(m-C₆H₄SO₃Na)₃ (TPPTS) and less active than tri(4,6-dimethyl-3-sulfonatophenyl)phosphine trisodium salt (TXPTS). Activated, deactivated, and sterically hindered aryl bromides were examined, with yields ranging from 50% to 90% in 6 h with 5% palladium precatalyst loading. X-ray crystal structures of (RO-PTA)PdCl₂, (PTA_R3)₂PdCl₂ (R = Ph, p-tert-butylC₆H₅), and PTA_R3 (R = p-tert-butylC₆H₅) are reported.

【 授权许可】

CC BY   
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