title: The Suzuki reaction in aqueous media promoted by P, N ligands.
abstract: 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.
authors.affiliation: Department of Chemistry, University of Nevada, Reno NV 89557, USA.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Weeden
authors.forename: Rongcai
authors.initials: R
authors.lastname: Huang
authors.forename: Kathryn D
authors.initials: KD
authors.lastname: Galloway
authors.forename: Phillip W
authors.initials: PW
authors.lastname: Gingrich
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Frost
mesh_terms: D000218:Adamantane / Q000031:analogs & derivatives; D001897:Boronic Acids / Q000737:chemistry*; D001965:Bromides / Q000737:chemistry*; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods*; D018360:Crystallography, X-Ray; D007306:Insecticides / Q000138:chemical synthesis*; D008024:Ligands; D009584:Nitrogen / Q000737:chemistry; D009943:Organophosphorus Compounds; D010165:Palladium / Q000737:chemistry*; D010720:Phosphines / Q000138:chemical synthesis*; D010758:Phosphorus / Q000737:chemistry; D012995:Solubility; D014867:Water
chemical_list: C501763:1,3,5-triaza-7-phosphaadamantane; D001897:Boronic Acids; D001965:Bromides; D007306:Insecticides; D008024:Ligands; D009943:Organophosphorus Compounds; D010720:Phosphines; D014867:Water; D010758:Phosphorus; D010165:Palladium; C010686:benzeneboronic acid; D009584:Nitrogen; C008756:palladium chloride; D000218:Adamantane