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DOI: 10.1055/s-2007-986639
Palladium-Doped Mixed Oxides as ‘Slow-Release’ Catalysts for Suzuki Couplings
Publikationsverlauf
Publikationsdatum:
28. August 2007 (online)
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Abstract
Palladium-containing sol-gel materials are efficient catalysts for Suzuki couplings. Especially good results are obtained under microwave irradiation in water. At least in this solvent, homogeneous palladium species are responsible for the catalytic activity.
Key words
cross-couplings - boronic acids - microwave irradiation - sol-gel catalysts - Suzuki couplings
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1a
Miyaura N.Suzuki A. Chem. Rev. 1995, 95: 2457 -
1b
Hassan J.Sevignon M.Gozzi C.Schulz E.Lemaire M. Chem. Rev. 2002, 102: 1359 -
1c
Miyaura N. Top. Curr. Chem. 2002, 11 -
1d
Miyaura N. In Metal-Catalyzed Cross-Coupling Reactions 2nd ed.:de Meijere A.Diederich F. Wiley-VCH; Weinheim: 2004. p.41 ; and references cited therein -
2a
Sakurai H.Tsukuda T.Hirao T. J. Org. Chem. 2002, 67: 2721 -
2b
Heiderich RG.Köhler K.Krauter JGE.Pietsch J. Synlett 2002, 1118 -
2c
Conlon DA.Pipik B.Ferdinand S.LeBlond CR.Sowa JR.Izzo B.Collins P.Ho G.-J.Williams JM.Shi Y.-J.Sun Y. Adv. Synth. Catal. 2003, 345: 931 -
2d
Lysen M.Köhler K. Synthesis 2006, 692 -
2e
Seki M. Synthesis 2006, 2975 -
2f
Felpin F.-X.Ayad T.Mitra S. Eur. J. Org. Chem. 2006, 2679 ; and references cited therein -
3a
Bulut H.Artok L.Yilmaz S. Tetrahedron Lett. 2003, 44: 289 -
3b
Artok L.Bulut H. Tetrahedron Lett. 2004, 45: 3881 - 4
Shimizu K.Maruyama R.Komai S.Kodama T.Kitayama Y. J. Catal. 2004, 227: 202 -
5a
Choudary BM.Madhi S.Chowdari NS.Kantam ML.Sreedhar B. J. Am. Chem. Soc. 2002, 124: 14127 -
5b
Kantam ML.Subhas MS.Roy S.Roy M. Synlett 2006, 633 -
6a
Kabalka GW.Pagni RM.Hair CM. Org. Lett. 1999, 1: 1423 -
6b
Kantam ML.Roy S.Roy M.Sreedhar B.Choudary BM. Adv. Synth. Catal. 2005, 347: 2002 -
6c
Cwik A.Hell Z.Figueras F. Org. Biomol. Chem. 2005, 3: 4307 -
7a
Davies IW.Matty L.Hughes DL.Reider PJ. J. Am. Chem. Soc. 2001, 123: 10139 -
7b
Prockl SS.Kleist W.Gruber MA.Köhler K. Angew. Chem. Int. Ed. 2004, 43: 1881 -
7c
Phan NTS.van der Sluys M.Jones CW. Adv. Synth. Catal. 2006, 348: 609 -
7d
Yin L.Liebscher J. Chem. Rev. 2007, 107: 133 ; and references cited therein -
8a
Biffis A.Zecca M.Basato M. Eur. J. Inorg. Chem. 2001, 1131 -
8b
Na Y.Park S.Han SB.Han H.Ko S.Chang S. J. Am. Chem. Soc. 2004, 126: 250 -
8c
Jaska CA.Manners I. J. Am. Chem. Soc. 2004, 126: 9776 - 9
Smith MD.Stepan AF.Ramarao C.Brennan PE.Ley SV. Chem. Commun. 2003, 2652 - 10
Nishihata Y.Mizuki J.Akao T.Tanaka H.Uenishi M.Kimura M.Okamoto T.Hamada N. Nature (London) 2002, 418: 164 - 11
Andrews SP.Stepan AF.Tanaka H.Ley SV.Smith MD. Adv. Synth. Catal. 2005, 347: 647 - 12
Lipshutz BH.Tasler S.Chrisman W.Spliethoff B.Tesche B. J. Org. Chem. 2003, 68: 1177 - 13
Frenzer G.Maier WF. Annu. Rev. Mater. Res. 2006, 36: 281 - 14
Kim DK.Maier WF. J. Catal. 2006, 238: 142 - 16
Maier WF.Stöwe K.Sieg S. Angew. Chem. Int. Ed. 2007, 46: 6016 -
17a
Kappe CO. Angew. Chem. Int. Ed. 2004, 43: 6250 -
17b
Arvela RK.Leadbeater LE. Org. Lett. 2005, 7: 2101 - 19
Shirakawa E.Yamasaki K.Hiyama T. Synthesis 1998, 1544 -
20a
Tagata T.Nishida M. J. Org. Chem. 2003, 68: 9412 -
20b
Arcadi A.Cerichelli G.Chiarini M.Correa M.Zorzan D. Eur. J. Org. Chem. 2003, 4080 -
20c
Lysen M.Köhler K. Synlett 2005, 1671 - 22
Moreno-Mañas M.Pérez M.Plaixats R. J. Org. Chem. 1996, 61: 2346 - For some other reports about cross-couplings with ‘homeopathic’ amounts of Pd, see:
-
24a
de Vries AHM.Parlevliet FJ.Schmieder van de Vondervoort L.Mommers JHM.Henderickx HJW.Walet AM.de Vries JG. Adv. Synth. Catal. 2002, 344: 996 -
24b
de Vries AHM.Mulders JMCA.Mommers JHM.Henderickx HJW.de Vries JG. Org. Lett. 2003, 5: 3285 -
24c
Schmidt AF.Smirnov VV. J. Mol. Catal. A: Chem. 2003, 203: 75 -
24d
Alimardanov A.de Vondervoort LSV.de Vries AHM.de Vries JG. Adv. Synth. Catal. 2004, 346: 1812 -
24e
Arvela RK.Leadbeater NE.Sangi MS.Williams VA.Granados P.Singer RD. J. Org. Chem. 2005, 70: 161
References and Notes
Preparation of Catalysts: The catalysts were prepared by a modified sol-gel method. The following precursors, Cu(NO3)2·3H2O, Fe(NO3)3·9H2O, La(NO3)3·6H2O, Ni(NO3)2·6H2O, and Pd(NO3)2·H2O, were dissolved in distilled H2O and mixed with ethylene glycol and nitric acid. The molar ratio was M/H2O/ethylene glycol/HNO3 = 1:40:20:4 (M as the sum of metal ions). The solutions were dried and calcined in air for 12 h at 80 °C, for 60 h at 105 °C and for 5 h at 400 °C with a heating rate of 6 °C/ h each. After calcination the powders were ground and sieved.
18
General Procedure for Suzuki Couplings in EtOH-Toluene: To a two-phase system of toluene (4 mL), EtOH (1.3 mL) and 2 M K2CO3 (2 mL), aryl halide (1.0 mmol), boronic acid (1.1 mmol) and catalyst (for mol% of Pd see Table
[1]
) were added and the mixture was heated to reflux for the specified time. After cooling to r.t., H2O was added and the aqueous layer was extracted with Et2O (3 ×). After drying (Na2SO4) and evaporation of the solvent, the crude product was purified by column chromatography (silica gel, hexanes-EtOAc).
4-Benzyloxy-4′-methoxybiphenyl (3): According to this general procedure 3 was obtained from 4-bromoanisole (187 mg) and 4-benzyloxyphenylboronic acid (251 mg) as a white solid; mp 170 °C. 1H NMR (500 Hz, CDCl3): δ = 7.45 (m, 6 H), 7.40 (dd, J = 7.3, 7.7 Hz, 2 H), 7.34 (t, J = 7.3 Hz, 1 H), 7.04 (d, J = 8.7 Hz, 2 H), 6.96 (d, J = 8.7 Hz, 2 H), 5.11 (s, 2 H), 3.85 (s, 3 H). 13C NMR (500 Hz, CDCl3): δ = 158.7, 157.9, 137.0, 133.7, 133.4, 128.6, 128.0, 127.7, 127.5, 115.1, 114.2, 70.1, 55.3. Anal. Calcd for C20H18O2 (290.36): C, 82.73; H, 6.25. Found: C, 82.99; H, 6.45. HRMS: m/z [M+] calcd for C20H18O2: 290.1307; found: 290.1340.
General Procedure for Suzuki-Couplings in Water under Microwave Irradiation: In a glass tube were placed aryl halide (1 mmol), phenylboronic acid (183 mg, 1.5 mmol), catalyst (1.2 mol%), 2 M K2CO3 (2 mL) and H2O (4 mL). The sealed vessel was placed into the microwave. The mixture was irradiated in a sealed tube at 150 °C (initial power 100 W). After 60 min the reaction was cooled to r.t. Then H2O was added and the aqueous layer was extracted with Et2O (3 ×). After drying (Na2SO4) and evaporation of the solvent, the crude product was purified by column chromatography (silica gel, hexanes-EtOAc).
4-Nitrobiphenyl (8a): yellow solid; mp 112 °C. 1H NMR (500 Hz, CDCl3): δ = 8.30 (d, J = 8.9 Hz, 2 H), 7.74 (d, J = 8.9 Hz, 2 H), 7.63 (d, J = 7.1 Hz, 2 H), 7.50 (dd, J = 7.1, 7.5 Hz, 2 H), 7.45 (t, J = 7.5 Hz, 1 H). 13C NMR (500 Hz, CDCl3): δ = 147.6, 147.1, 138.7, 129.1, 128.9, 127.8, 127.4, 124.1.
2-Hydroxybiphenyl (8b): white solid; mp 57 °C. 1H NMR (500 Hz, CDCl3): δ = 7.52-7.55 (m, 4 H), 7.44 (m, 1 H), 7.28-7.33 (m, 2 H), 7.03-7.06 (m, 2 H), 5.32 (br s, 1 H). 13C NMR (500 Hz, CDCl3): δ = 152.4, 137.1, 130.2, 129.2, 129.1, 129.1, 128.1, 127.8, 120.8, 115.8.
4-Hydroxybiphenyl (8c): white solid; mp 57 °C. 1H NMR (500 Hz, CDCl3): δ = 7.55 (d, J = 7.5 Hz, 2 H), 7.49 (d, J = 8.6 Hz, 2 H), 7.42 (dd, J = 7.4, 7.5 Hz, 2 H), 7.31 (t, J = 7.4 Hz, 1 H), 6.91 (d, J = 8.6 Hz, 2 H), 4.81 (br s, 1 H).13C NMR (500 Hz, CDCl3): δ = 155.0, 140.7, 134.1, 128.7, 128.4, 126.7, 115.6.
Biphenyl-4-carboxylic Acid (8d): white solid; mp 215 °C. 1H NMR (500 Hz, DMSO-d
6): δ = 13.00 (br s, 1 H), 8.03 (d, J = 8.4 Hz, 2 H), 7.79 (d, J = 8.4 Hz, 2 H), 7.73 (d, J = 7.4 Hz, 2 H), 7.50 (dd, J = 7.4, 7.6 Hz, 2 H), 7.42 (t, J = 7.6 Hz, 1 H), 3.87 (s, 3 H). 13C NMR (500 Hz, DMSO-d
6): δ = 167.1, 144.2, 138.9, 131.6, 129.9, 129.0, 128.2, 126.9, 126.7.
Biphenyl-4-ylamine (8e): orange-brown solid (162 mg, 0.96 mmol, 96%); mp 53 °C. 1H NMR (500 Hz, CDCl3): δ = 7.57 (dd, J = 1.2, 8.2 Hz, 2 H), 7.45 (d, J = 8.4 Hz, 2 H), 7.41 (dd, J = 7.3, 8.2 Hz, 2 H), 7.30 (dt, J = 1.2, 7.3 Hz, 1 H), 6.77 (d, J = 8.4 Hz, 2 H), 3.73 (br s, 2 H). 13C NMR (500 Hz, CDCl3): δ = 145.8, 141.1, 131.5, 128.6, 128.0, 126.4, 126.2, 115.3.
Biphenyl-3-carbaldehyde (8f): colorless liquid. 1H NMR (500 Hz, CDCl3): δ = 10.09 (s, 1 H), 8.11 (dd, J = 1.6, 1.6 Hz, 1 H), 7.86 (dd, J = 1.6, 7.7 Hz, 2 H), 7.63 (d, J = 7.7 Hz, 2 H), 7.61 (dd, J = 7.7, 7.7 Hz, 1 H), 7.48 (dd, J = 7.3, 7.7 Hz, 2 H), 7.41 (t, J = 7.3 Hz, 1 H). 13C NMR (500 Hz, CDCl3): δ = 192.2, 142.1, 139.6, 136.9, 133.0, 129.4, 128.9, 128.6, 128.1, 128.0, 127.1.
4-Methoxybiphenyl (8g): white solid; mp 88 °C. 1H NMR (500 Hz, CDCl3): δ = 7.54-7.58 (sh, 4 H), 7.48 (dd, J = 7.5, 7.9 Hz, 2 H), 7.32 (t, J = 7.5 Hz, 1 H), 7.00 (d, J = 8.8 Hz, 2 H), 3.87 (s, 3 H). 13C NMR (500 Hz, CDCl3): δ = 159.1, 140.8, 133.8, 128.7, 128.1, 126.7, 126.6, 114.2, 55.3.
5-Phenylpyrimidine (8h): white solid; mp 41 °C. 1H NMR (500 Hz, CDCl3): δ = 9.21 (s, 1 H), 8.95 (s, 2 H), 7.58 (d, J = 7.5 Hz, 2 H), 7.52 (dd, J = 7.2, 7.5 Hz, 2 H), 7.47 (t, J = 7.2 Hz, 1 H). 13C NMR (500 Hz, CDCl3): δ = 157.5, 154.9, 134.3, 134.3, 129.4, 129.0, 127.0.
Biphenyl-4-carbaldehyde (8i): white solid; mp 59 °C. 1H NMR (500 Hz, CDCl3): δ = 10.06 (s, 1 H), 7.95 (d, J = 8.3 Hz, 2 H), 7.75 (d, J = 8.3 Hz, 2 H), 7.64 (d, J = 7.1 Hz, 2 H), 7.50 (dd, J = 7.1, 7.5 Hz, 2 H), 7.42 (t, J = 7.5 Hz, 1 H). 13C NMR (500 Hz, CDCl3): δ = 191.8, 147.1, 139.6, 135.1, 130.2, 128.9, 128.4, 127.6, 127.3.
Determination of Pd and La Concentrations in Solution with ICP-MS: ICP-MS was conducted with a VG Elemental Plasma Quad 3 instrument. The examined isotopes were 105Pd and 139La. Calibration was carried out with external standards of 10 ppt, 100 ppt, 1 ppb, 2 ppb, 5 ppb, 10 ppb and 100 ppb palladium and lanthanum. The freshly irradiated (100 W, 150 °C, 1 h) and filtered solution of catalyst C was diluted to 1:20, 1:30, 1:100 and 1:200. A 3% nitric acid solution was added to all samples. The average of the Pd and La concentrations in solution was calculated from these acquired concentrations.