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Gold Catalysis

Gold Catalysis. Outline. General properties of gold: - The element - Facts and myths. Heterogeneous catalysis (briefly): - Main characteristics - Examples: ethyne hydrochlorination, oxidations, hydrogenation, …. Homogeneous catalysis - Overview

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Gold Catalysis

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  1. Gold Catalysis

  2. Outline • General properties of gold: • - The element • - Factsandmyths • Heterogeneous catalysis (briefly): • - Main characteristics • - Examples: ethyne hydrochlorination, oxidations, hydrogenation, … • Homogeneous catalysis • - Overview • - Gold as an oxidant • - Gold as an Lewis Acid • - C-H activation • - Alkyne activation • - Allene activation • - Asymmetric reaction • - Recent literature • Conclusion • Questions?

  3. Gold: The Element 11

  4. Gold: The Element • Name: from the Sanskrit word Jval and the Anglo-Saxon gold. Gold’s chemical symbol comes from the Latin word Aurum. Known for at least5500years. • Sources: generally in conjunction with silver, quartz (SiO2), calcite (CaCO3), lead, tellurium, zinc or copper. 2/3 of the world’s gold comes from South Africa. It is present in sea water: about 0.1 to 2 mg/ton, but no isolation method has been developed. • Characteristic: most malleable and ductile metal, good conductor of heat and electricity, not attacked by oxygen or sulfur. Reacts with halogens (e.g. aqua regia dissolved gold). Soft metal, so it is alloyed with others metals like Ag, Cu, Pt and Pd to increase the strength (e.g. application in jewelry). • Applications: the isotope Au-198 (half-life 2.7 days) used for treating cancer. AuNa3O6S4 (gold sodium thiosulfate) used for arthritis. HAuCl4 (chlorauric acid) used to preserve photographs by replacing the silver atoms.

  5. Gold: The Element • Electron configuration: [Xe] 6s1 4f14 5d10 • Oxidation States: from –I to III and +V • Most commonGold (I) and Gold (III) complex, both used in homogeneous catalysis. • Prices for 1g (STREM catalog 2004-06): Au Pt Pd Rh Ru AuCl86$ PtCl70$ PdCl2 38$ RhCl(PPh3)42$ very expensive AuBr3 55$ PtO2 76$ Pd(OAc)2 52$ RhCl3 136$ c.f. Christopher’s presentation HAuCl440$ Pt 110$ Pd2(dba)366$ Rh(acac)2 134$ PPh3AuCl125$ (Alfa Aesar)

  6. Gold: Facts and Myths FALSE: • Gold is chemically inert and uninteresting • Gold is expensive (cheaper than Platinum) TRUE: • Gold is stable in the presence of oxygen and water • Gold can be used for heterogeneous and homogeneous catalysis When is it convenient to use gold as a catalyst? (A. S.K. Hashmi Gold Bull.2004, 51-65) “The use of gold as a catalyst is desirable when it shows similar activity as for a more expensive catalyst or higher selectivity than a less expensive catalyst and when a new transformation is possible”.

  7. Outline • General properties of gold: • - The element • - Factsandmyths • Heterogeneous catalysis (briefly): • - Main characteristics • - Examples: ethyne hydrochlorination, oxidations, hydrogenation, … • Homogeneous catalysis • - Overview • - Gold as an oxidant • - Gold as an Lewis Acid • - C-H activation • - Alkyne activation • - Allene activation • - Asymmetric reaction • - Recent literature • Conclusion • Questions?

  8. Heterogeneous Catalysis Key Features: • Particle size (1 and 10 nm in diameter) • Nature of the support (transition metal oxide, carbon, zeolite) Active Catalyst: supported small metallic gold particles Advantages: • High catalytic activity (small amounts are necessary) • Mild conditions (low temperature, low pressure) • Good resistance to deactivation INDUSTRIAL APPLICATIONS G. J. Hutchings Catal. Today 2005, 55-61; C. W. Corti, R. J. Holliday, D. T. Thompson Catal. Today 2005, 253-261.

  9. Heterogeneous Catalysis • Ethyne (acetylene) Hydrochlorination PVC market G. J. Hutchings J. Catal. 1985, 292-295; G. J. HutchingsGold Bull. 1996, 123. Advantages: • 3x more reactive than the traditional HgCl2 • catalyst recycling 2. CO Oxidation at Low Temperature Industrial, environmental and domestic sectors M. Haruta, T. Kobayashi, H. Sano, N. Yamada Chem. Lett. 4, 1987, 405. Anhydrous conditions necessary Not active at ambient temperature Catalyst: Hopcalyte (mixed oxide of Mn and Cu) More active and stable Activity at -70 ºC Au/Fe2O3 or Co3O4

  10. Heterogeneous Catalysis 3. Oxidations Mediated by O2 High temperatures are necessary (270 - 720 ºC) and product mixtures are observed. Catalyst: 1% Au/C (reagent/catalyst= 1000) conversion: 96% selectivity: 98% 1% Au/TiO2 conversion: 95% selectivity: 98% 5% Pd or Pt/C selectivity:77% 1% Au/C conversion: 22% selectivity: 100% 1% Au/Al2O3 conversion: 100% selectivity: 100% 5% Pd or Pt/C no reaction S. Biella, G.L. Castiglioni, C. Fumagalli, L. Prati, M. Rossi Catal. Today 2002, 43-49.

  11. Heterogeneous Catalysis 3. Oxidations Mediated by O2 1% Au/graphite O2 3 atm, NaOH aq 60ºC, 3h conversion: 56% selectivity: 100% 5% Pt/C 55% O2 6 atm, NaOH aq 60ºC, 3h conversion:88% selectivity:63% 23% S. Carrettin, P. McMorn, C. Fumagalli, P. Johnston, K. Griffin, G. J. Hutchings Chem. Commun. 2002, 696-697.

  12. Heterogeneous Catalysis 4. Selective Hydrogenation (under H2 pressure) Extended studies on the size particles, supports and synthesis technique on the selectivity. P. Claus Appl. Catalysis A: General 2005, 222-229.

  13. Heterogeneous Catalysis 4. Selective Hydrogenation Au/SiO2 Pt, Pd and Rh S. Schimpf, M. Lucas, C. Mohr, U. Rodemerck, A. Bruckner, J. Radnik, H. Hofmeister, P. Claus Catal. Today 2002, 63-78.

  14. Heterogeneous Catalysis 5. Industrial Application: Commercial Uses (Patent) C. W. Corti, R. J. Holliday, D. T. Thompson Appl. Catalysis A: General 2005, 253-261.

  15. Outline • General properties of gold: • - The element • - Factsandmyths • Heterogeneous catalysis (briefly): • - Main characteristics • - Examples: ethyne hydrochlorination, oxidations, hydrogenation, … • Homogeneous catalysis • - Overview • - Gold as an oxidant • - Gold as an Lewis Acid • - C-H activation • - Alkyne activation • - Allene activation • - Asymmetric reaction • - Recent literature • Questions?

  16. Homogeneous Catalysis Key Features: • Soft transition metal, soft partners such as carbon are preferred. • Often reactions are faster than other transition metals. In some cases a completely new product is formed. • Low propensity for β-H elimination. • Organogold intermediates undergo fast protodemetallation. • Cross-coupling chemistry seems difficult due to the easy reduction (difficult oxidation) of gold. • It has been shown that often reactions are possible with both Au (I) and Au (III), so the real catalytic species is not known. On the other hand, in some cases different products are observed for the different oxidation states. A. S.K. Hashmi Gold Bull.2003, 3-9; A. S.K. Hashmi Gold Bull.2004, 51-65; A. S.K. Hashmi Angew. Chem. Int. Ed.2005, 44, 6990-6993. A. Arcadi, S. Di Giuseppe Curr. Org. Chem.2004, 8, 795-812; A. Hoffmann-Roder, N. Krause Org. Biol. Chem.2005, 3, 387-391.

  17. Homogeneous Catalysis • Gold as an oxidant 1.1 Thioether Oxidation F. Gasparrini, M. Giovannoli, D. Misiti, G. Natile, G. Palmieri Tetrahedron 1983, 39, 3181-3184 and 1984, 40, 165-170. 1.2 Oxidative Alkyne Coupling F. Gasparrini, M. Giovannoli, D. Misiti, G. Natile, G. Palmieri, L. Maresca J. Am. Chem. Soc. 1993, 115, 4401-4402. 1.3 Baeyer-Villiger Oxidation J. Sundermeyer, C. Jost DE 10041510 1999.

  18. Homogeneous Catalysis 2. Gold as a Lewis Acid 2.1 Michael Addition S. Kobayashi, K. Kakumoto, M. Sugiura Org. Lett. 2002, 4, 1319-1320. 2.2 Carbonyl-amine condensation A. Arcadi, M. Chiarini, S. Di Giuseppe Green Chemistry 2003, 5, 64-67.

  19. Homogeneous Catalysis 2. Gold as a Lewis Acid (continue) 2.3 Friendländer Quinoline Synthesis A. Arcadi, M. Chiarini, S. Di Giuseppe, F. Marinelli Synlett 2003, 203-206.

  20. Homogeneous Catalysis 2. Gold as a Lewis Acid (continue) A. Arcadi, M. Chiarini, S. Di Giuseppe, F. Marinelli Synlett 2003, 203-206.

  21. Homogeneous Catalysis 3. C-H Activation Hydroarylation of Alkynes Y. Fuchita, Y. Utsunomiya, M. Yasutake J. Chem. Soc., Dalton Trans. 2001, 2330-2334. M. T. Reetz, K. Sommer Eur.J. Org. Chem. 2003, 3485-3496.

  22. Homogeneous Catalysis 3. C-H Activation 1M. T. Reetz, K. Sommer Eur.J. Org. Chem. 2003, 3485-3496. 2Z. Shi, C. He J. Org. Chem. 2004, 69, 3669-3671. Proposed Mechanism: M. T. Reetz, K. Sommer Eur.J. Org. Chem. 2003, 3485-3496.

  23. Homogeneous Catalysis 3. C-H Activation Z. Shi, C. He J. Am. Chem. Soc. 2004, 126, 5964-5965. Z. Shi, C. He J. Org. Chem. 2004, 69, 3669-3671. X. Yao, C. -H. Li J. Am. Chem. Soc. 2004, 126, 6884-6885. Also applied to diene, triene and cyclic enol ethers! Y. Luo, C. -H. Li Chem. Comm. 2004, 1930-1931. Li and Al. Org. Lett. 2005, 7, 673-675.

  24. Homogeneous Catalysis 4. Alkynes Activation 4.1 Nucleophilic Addition to Alkynes O-Nucleophile N-Nucleophile Tetrahydropyridine 1Y. Fukuda, K, Utimoto J. Org. Chem. 1991, 56, 3729-3731. 2J. H Teles, S. Brode, M. Chabanas Angew. Chem. Int. Ed. 1998, 37, 1415-1418. 3Y. Fukuda, K, Utimoto Synthesis. 1991, 975-978.

  25. Homogeneous Catalysis 4. Alkyne Activation 4.1 Nucleophilic Addition to Alkynes Pyrroles1 Indoles2 1A. Arcadi, S. Di Giuseppe, F. Marinelli, E. Rossi Adv. Syn. Catal. 2001, 5, 343-6346. 2A. Arcadi, G. Bianchi, F. Marinelli Synthesis 2004, 4, 610-618.

  26. Homogeneous Catalysis 4. Alkyne Activation 4.1 Nucleophilic Addition to Alkynes Pyridines G. Abbiati, A. Arcadi, G. Bianchi, S. Di Giuseppe, F. Marinelli, E. Rossi J. Org. Chem. 2003, 68, 6959-6966.

  27. Homogeneous Catalysis 4. Alkyne Activation 4.1 Nucleophilic Addition to Alkynes Pyridines NaAuCl4 2.5 % EtOH reflux 6-endo-dig 46-98% G. Abbiati, A. Arcadi, G. Bianchi, S. Di Giuseppe, F. Marinelli, E. Rossi J. Org. Chem. 2003, 68, 6959-6966.

  28. Homogeneous Catalysis 4. Alkyne Activation 4.2 Furan Isomerisation R R 3 4 R Same conditions! R R A. S. K. Hashmi, T. M. Frost, W. Bats J. Am. Chem. Soc. 2000, 122, 11553-11554.

  29. Homogeneous Catalysis 4. Alkyne Activation 4.2 Furan Isomerisation: Synthesis of Jungianol 75% 0% 0% Jungianol 7% 68% 21% A. S. K. Hashmi, T. L. Ding, W. Bats, P. Fischer, W. Frey Chem. Eur. J. 2003, 9, 4339-4345.

  30. Cu(OTf)2 1 3 AuX3 11 Homogeneous Catalysis 4. Alkyne Activation 4.3 Benzoannulation AuX3 N. Asao, T. Nogami, S. Lee, Y. Yamamoto J. Am. Chem. Soc. 2003, 125, 10921-10925.

  31. Homogeneous Catalysis 4. Alkyne Activation 4.4 5-exo-dig and 5-endo-dig Carbocyclisation 5-exo-dig 1 5-exo-dig 93% 5 3 2 4 Conditions:1%Au(PPh3)Cl, 1% AgOTf CH2Cl2, r.t 5 min to 24 h J. J. Kennedy-Smith, A. T. Staben, F. D. Toste J. Am. Chem. Soc. 2004, 126, 4526-4527.

  32. Homogeneous Catalysis 4. Alkyne Activation 4.4 5-exo-dig and 5-endo-dig Carbocyclisation 1 5-endo-dig 3 2 5 4 A. T. Staben, J. J. Kennedy-Smith, F. D. Toste Angew. Chem. Int. Ed. 2004, 43, 5350-5352.

  33. Homogeneous Catalysis 4. Alkyne Activation 4.5 Cycloisomerisation C. Nieto-Oberhumber, M. Paz Munoz, E. Bunuel, C. Nevado, D. J. Cardenas, A. M. Echavarren Angew. Chem. Int. Ed. 2004, 43, 2402-2406.

  34. Homogeneous Catalysis 4. Alkyne Activation 4.5 Cycloisomerisation (continue) PtCl2 shows broader scope Au(I) vs. Au(III) 1M. Mendez, M. Paz Munoz, E. Bunuel, C. Nevado, D. J. Cardenas, A. M. Echavarren J. Am. Chem. Soc. 2001, 123, 10510-10520. 2C. Nieto-Oberhumber, M. Paz Munoz, E. Bunuel, C. Nevado, D. J. Cardenas, A. M. Echavarren Angew. Chem. Int. Ed. 2004, 43, 2402-2406.

  35. Homogeneous Catalysis 4. Alkynes Activation 4.5 Cycloisomerisation (Nolan) 1P. De Frémont, N. M. Scott, E. D. Stevens, S. P. NolanOrgaometallics. 2005, 24, 2411-2418. 2S. P. Nolan and al. Chem. Commun. (ASAP). 3 S. P. Nolan and al. Angew. Chem. Int. Ed.(on press).

  36. Homogeneous Catalysis 5. Allene Activation 5.1 Cycloisomerisation of α-hydroxyallenes1,2 Classical conditions: HCl(g) in CHCl3 or stoichiometric AgNO3 1A. Hoffmann-Roder, N. Krause Org. Lett. 2001, 3, 2537-2538. 2N. Krause, A. Hoffmann-Roder, J. Canisius Synthesis 2002, 12, 1759-1774.

  37. Homogeneous Catalysis 5. Allene Activation 5.2 Cycloisomerisation of α-amino-1 and α-thio- allenes2 3-pyrrolines 2,5-dihydrothiophenes AuCl (5%) 88% 1N. Morita, N. Krause Org. Lett. 2004, 6, 4121-2123. 2N. Morita, N. Krause Anew. Chem. Int. Ed. 2006, 45, 1897-1899.

  38. Homogeneous Catalysis 5. Allene Activation Proposed Mechanism: In the case of α-thioallenes more investigation are necessary to established the catalytic species!

  39. Homogeneous Catalysis 6. Asymmetric Reactions 6.1 Asymmetric Aldol Condensation Proposed transition state: I. Yoshihiko, M. Sawamura, T. Hayashi J. Am. Chem. Soc. 1986, 108, 6405-6406.

  40. Homogeneous Catalysis 6. Asymmetric Reactions 6.1 Asymmetric Aldol Condensation balanol 90% dr 19:1% ee > 99% threo-3-hydroxylysine P. F. Hughes, S. H. Smith, J. T. Olson J. Org. Chem. 1994, 58, 5799-5802.

  41. Homogeneous Catalysis 6. Asymmetric Reactions 6.2 Asymmetric Cycloisomerisation 5% PtCl2, MeOH, (S)-TolBINAP, 80ºC 94%, 48% ee (-) M.P. Munoz, J. Adrio, J.C. Carrettero, A.M. Echavarren Organometallics 2005, 24, 1293-1300.

  42. Homogeneous Catalysis 6. Asymmetric Reactions 6.3 Asymmetric Hydrogenation C. Gonzalez-Arellano, A. Corma, M. Iglesias, F. Sanchez Chem. Commun. 2005, 3451-3153.

  43. Homogeneous Catalysis Recent Literature: Nucleophilic Attack to Unactivated Alkenes 1 2 3 1C.-G. Yang, C. He J.Am. Chem. Soc. 2005, 127, 6966-6967. 2J. Zhang, C.-G. Yang, C. He J.Am. Chem. Soc. 2006, 128, 1798-1799. 3C. Brouver, C. He Angew. Chem. Int. Ed. 2006, 45, 1744-1747.

  44. X X X R R R Conclusion Au (I) or Au (III)? Au(PEt3)Cl X= Cl, Br, I Toluene, 5 min to 3 days 1 2 3 AuCl3 A. W. Someck, M. Rubina, V. Gevorgyan J. Am. Chem. Soc. 2005, 127, 10500-10501.

  45. [[[(Dimethylammino)methylene]amino]-methylene]dimethylammonium Chloride1 It is a brown solid and it is a β-dimethylaminomethylenating agent for ketones and amines2 1Encyclopedia of Reagents for Organic Synthesis (Ed L.A. Paquette) Vol3, 1995, 2014. 2J. T. Gupton, C. Colon, C. R. Harrison, M. J. Lizzi, D. E. Polk J. Org. Chem. 1980, 45, 4522-4524. Questions? What is the Gold’s reagent?

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