Abstract: The synthesis and structure of palladium complexes of trisubstituted PTA derivatives, PTAR3, 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 [22.214.171.124]decane, and 2,4,6-triphenyl-1,3,5-triaza-7-phosphatricyclo[126.96.36.199]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, (PTAR3)2PdCl2 (R = Ph, p-tert-butylC6H5), and PTAR3 (R = p-tert-butylC6H5) are reported.
This is an open access article distributed under the
Creative Commons Attribution License which permits unrestricted use, distribution,
and reproduction in any medium, provided the original work is properly cited.
Export to BibTeX
MDPI and ACS Style
Weeden, J.A.; Huang, R.; Galloway, K.D.; Gingrich, P.W.; Frost, B.J. The Suzuki Reaction in Aqueous Media Promoted by P, N Ligands. Molecules 2011, 16, 6215-6231.
Weeden JA, Huang R, Galloway KD, Gingrich PW, Frost BJ. The Suzuki Reaction in Aqueous Media Promoted by P, N Ligands. Molecules. 2011; 16(8):6215-6231.
Weeden, Jason A.; Huang, Rongcai; Galloway, Kathryn D.; Gingrich, Phillip W.; Frost, Brian J. 2011. "The Suzuki Reaction in Aqueous Media Promoted by P, N Ligands." Molecules 16, no. 8: 6215-6231.