1 Homogeneous Gold Catalysis – A Reactivity Perspective Dongxu Shu Tang Research Group 12, 10,...

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1 Homogeneous Gold Catalysis Homogeneous Gold Catalysis – A Reactivity Perspective – A Reactivity Perspective Dongxu Shu Dongxu Shu Tang Research Group Tang Research Group 12, 10, 2009 12, 10, 2009
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Transcript of 1 Homogeneous Gold Catalysis – A Reactivity Perspective Dongxu Shu Tang Research Group 12, 10,...

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1 Homogeneous Gold Catalysis A Reactivity Perspective Dongxu Shu Tang Research Group 12, 10, 2009 Slide 2 2 Contents Relativistic effect and reactivity -acidity reactivity Gold catalyzed coupling reaction Summary Slide 3 3 Features of Gold Catalysis -acidity: soft Lewis acid, preferentially activate -systems Au I and Au III Au I : d 10, linear bicoordinate geometry, difficult in asymmetric catalysis No-H elimination Reluctant to undergo oxidative addition and reductive elimination Slide 4 4 Relativistic Effect Lower 6s and 6p, higher 5d Pyykko, P. et al. Acc. Chem. Res. 1979, 12, 276. Slide 5 5 Origin of acidity and Alkynophilicity -acidity of R 3 PAu + 1)lower LUMO 2) poor back donation Alkynophilicity 1) kinetic in origin 2) LUMO of alkyne is lower Hertwig, R. H. et al. J. Phys. Chem. 1996, 100, 12253. Toste, F. D. et al. Nature. 2007, 446, 395. G -10 kcal/mol Slide 6 6 Contents Relativistic effect and reactivity -acidity reactivity 1. Alkyne 2. Enyne 3. Propargylic ester 4. Allene Gold catalyzed coupling reaction Summary Slide 7 7 -AcidityReactivity -Acidity Reactivity Slide 8 8 Carbene or Carbocation Frstner, A. et al. Angew. Chem. Int. Ed. 2009, 48, 2510. Slide 9 9 Carbene or Carbocation Goddard, W. A. Toste, F. D. et al. Nature Chem. 2009, 1, 482. Slide 10 10 Early Research Thomas, C. B. et al. J. Chem. Soc. Perkin Trans. II 1976, 1983. Teles, J. H. et al. Angew. Chem. Int. Ed. 1998, 37, 1415. Slide 11 11 Hashmi, A. S. K. et al. Angew. Chem. Int. Ed. 2009, 48, 8247. Stereoselectivity and Regioselectivity Slide 12 12 Contents Relativistic effect and reactivity -acidity reactivity 1. Alkyne 2. Enyne 3. Propargylic ester 4. Allene Gold catalyzed coupling reaction Summary Slide 13 13 Reactivity Pattern of Enyne Furstner, A. et al. Angew. Chem. Int. Ed. 2008, 47, 5030. Slide 14 14 Cycloisomerization of 1,6-Enyne With Skeletal Rearrangement Echavarren, A.M. et al. Angew. Chem. Int. Ed. 2004, 14, 2402. Echavarren, A.M. et al. Angew. Chem. Int. Ed. 2005, 44, 6146. Single Cleavage Double Cleavage Slide 15 15 Mechanism From Cyclobutene? Echavarren, A.M. et al. Chem. Eur. J. 2006, 12, 5916. Slide 16 16 Mechanism of Skeletal Rearrangement Single Cleavage Double Cleavage Echavarren, A.M. et al. Chem. Eur. J. 2006, 12, 5916. Slide 17 17 Toste, F. D. et al. J. Am. Chem. Soc. 2007, 129, 5838. Mechanism of Skeletal Rearrangement Slide 18 18 Contents Relativistic effect and reactivity -acidity reactivity 1. Alkyne 2. Enyne 3. Propargylic ester 4. Allene Gold catalyzed coupling reaction Summary Slide 19 19 Propargylic Ester Reactivity Pattern Nolan, S. P. et al. Angew. Chem. Int. Ed. 2007, 46, 2750. Slide 20 20 5-exo-dig VS 6-endo-dig Nolan, S. P. et al. Angew. Chem. Int. Ed. 2006, 45, 3647. Toste, F. D. et al. J. Am. Chem. Soc. 2009, 131, 4513. Slide 21 21 Carbene Reactivity through 5-exo-dig Uemura, S. et al. Tetrahedron Lett. 2003, 44, 2019. Toste, F. D. et al. J. Am. Chem. Soc. 2005, 127, 18002. Slide 22 22 Allene Activation through 6-endo-dig Zhang, L. et al. J. Am. Chem. Soc. 2005, 127, 16804. Zhang, L. et al. J. Am. Chem. Soc. 2007, 129, 11358. Slide 23 23 Contents Relativistic effect and reactivity -acidity reactivity 1. Alkyne 2. Enyne 3. Propargylic ester 4. Allene Gold catalyzed coupling reaction Summary Slide 24 24 Vinyl Allene as Substrate Malacria, M. et al. J. Am. Chem. Soc. 2009, 131, 2993. Slide 25 25 Vinyl Allene as Substrate Malacria, M. et al. J. Am. Chem. Soc. 2009, 131, 2993. Slide 26 26 Toste, F. D. et al. J. Am. Chem. Soc. 2009, 131, 6348. Mascarenas, J. L. et al. J. Am. Chem. Soc. 2009, 131, 13020. Allene for Cycloaddition Slide 27 27 Contents Relativistic effect and reactivity -acidity reactivity 1. Alkyne 2. Enyne 3. Propargylic ester 4. Allene Gold catalyzed coupling reaction Summary Slide 28 28 Early Investigation Kochi, J. K. et al. J. Organomet. Chem. 1974, 64, 411. Kochi, J. K. et al. J. Am. Chem. Soc. 1976, 98, 7599. Slide 29 29 Gold Catalyzed Coupling Reaction Corma, A. et al. Angew. Chem. Int. Ed. 2007, 46, 1536. Guo, R. et al. J. Am. Chem. Soc. 2009, 131, 386. Slide 30 Combine the -acidity and Coupling Reactivity Slide 31 Hashmi. A. S. K. et al. Eur. J. Org. Chem. 2006, 1387. Slide 32 Combine the -acidity and Coupling Reactivity Wegner. H. A. et al. Chem. Eur. J. 2008, 14, 11310. Slide 33 Zhang. L. et al. Angew. Chem. Int. Chem. 2009, 48, 3112. Oxidative Coupling Slide 34 Zhang. L. et al. Angew. Chem. Int. Chem. 2009, 48, 3112. Slide 35 Slide 36 36 Gold and Palladium Combined for Cross-Coupling Hashmi, A. S. K. et al. Angew. Chem. Int. Ed. 2009, 48, 8283. Blum, S. D. et al. Organometallics. 2009, 28, 1275. Slide 37 37 Summary -acidity reactivity Complexity 1. substrate design 2. coupled with known reactivity (Nazarov, cycloaddition, carbocation) 3. tandem Gold catalyzed coupling reaction Combine -acidity reactivity and coupling reaction 1. Generate more complexity 2. from stoichiometric to catalytic Slide 38 38 Acknowledgement Professor Weiping Tang Tang Group Practice talk attendees Katherine Myhre Jenny Werness Wei Zhang Renhe Liu Dr. Suqing Zheng Xiaoxun Li Dr. Min Zhang Patrick Robichaux Na Liu Kyle Dekorver Tianning Diao Slide 39 39 Goddard, W. A.; Toste, F. D. et al. Org. Lett. 2009, 11, 4798. Mascarenas, J. L. et al. J. Am. Chem. Soc. 2009, 131, 13020. Slide 40 Relativistic Effect m=m 0 /[1-(v/c) 2 ] 1/2 r decrease as m increase v increase, m increase, radius decrease, s and p orbital lower, d higher Unusual higher electronegativity, ionization energy, lower 6s and 6p (LUMO), higher 5d, strong Au-L bond Pyykko, P. et al. Acc. Chem. Res. 1979, 12, 276. Slide 41 General Reactivities of Gold Catalysis - Acidity: Traditional organometallic reactivity: Oxidative addition and reductive elimination Transmetallation C-H activation: Hydrogenation and Oxidation Slide 42