1 / 42

Asymmetric Frontiers in Lanthanide Catalysis

Asymmetric Frontiers in Lanthanide Catalysis. Andrew Lohse Hsung Group University of Wisconsin – Madison December 11, 2008. Overview. Background/Fundamentals Asymmetric Cycloadditions Multifunctional Asymmetric Catalysts C-C Bond Formation C-P Bond Formation C-O Bond Formation

yakov
Download Presentation

Asymmetric Frontiers in Lanthanide Catalysis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Asymmetric Frontiers in Lanthanide Catalysis Andrew Lohse Hsung Group University of Wisconsin – Madison December 11, 2008

  2. Overview • Background/Fundamentals • Asymmetric Cycloadditions • Multifunctional Asymmetric Catalysts • C-C Bond Formation • C-P Bond Formation • C-O Bond Formation • Conclusions/Future Directions

  3. Location

  4. The Lanthanide Contraction Mikami, K.; Terada, M.; Matsuzawa, H. Angew. Chem., Int. Ed. 2002, 41, 3554.

  5. Contracted Nature of the f-Orbitals • Shielded by 5s and 5p • Unavailable for bonding • Lack of orbital restrictions • No ligand field effects • Sterically saturated • Ionic character • “Hard” Lewis acids • Oxophilic • “triple-positively charged closed shell inert gas electron cloud” http://int.ch.liv.ac.uk/Lanthanide/Lanthanides.html Lanthanides: Chemistry and Use in Organic Synthesis; Kobayashi, S., Ed; Springer-Verlag: Berlin, 1999.

  6. Well-Known Examples in Synthesis Luche Reduction Evans-Tischenko Reduction Oxidative PMB Deprotection Luche, J. L. J. Am. Chem. Soc. 1978, 100, 2226. Evans, D. A.; Hoveyda, A. H. J. Am. Chem. Soc. 1990, 112, 6447. Green, T. W.; Wuts, P. G. M. Protective Groups in Organic Synthesis; John Wiley & Sons: New York, 1999.

  7. Why Use Lanthanides as Catalysts? • Variation of Size/Lewis Acidity Tunability • Nature of f orbitals • ionic character • high coordination #s • NMR Analysis • Diamagnetic: La3+, Ce4+, Yb2+, Lu3+ • Paramagnetic: Pr3+, Sm2+/3+, Eu3+ • Water/Air stable • Recyclable Crabtree, R. H. The Organometallic Chemistry of the Transition Metals, 4th ed; Wiley Interscience: New York, 2005. Lanthanides: Chemistry and Use in Organic Synthesis; Kobayashi, S., Ed; Springer-Verlag: Berlin, 1999.

  8. Aqueous Aldol • Use of ambient temperature • Less rigorous conditions • Recyclable Mukaiyama, T.; Banno, K.; Narasaka, K. J. Am. Chem. Soc.1974, 96, 7503. Kobayashi, S. Chem. Lett.1991, 2187.

  9. Historical Perspective Parker, D. Chem. Rev. 1991, 91, 1441. Aspinall, H. C. Chemistry of the f-Block Elements; Gordon and Breach: Amsterdam , 2001.

  10. Asymmetric Hetero-Diels-Alder Bednarski, M.; Maring, C.; Danishefsky, S. Tetrahedron Lett. 1983, 24, 3451. Mikami, K.; Terada, M.; Matsuzawa, H. Angew. Chem., Int. Ed. 2002, 41, 3554.

  11. Aza-Diels-Alder Kobayashi, S.; Ishitani, H., Araki, M.; Hachiya, I. Tetrahedron Lett. 1994, 35, 6325. Lanthanides: Chemistry and Use in Organic Synthesis; Kobayashi, S., Ed; Springer-Verlag: Berlin, 1999.

  12. Proposed Transition State • First catalytic asymmetric • aza-Diels-Alder • Lewis acid activation of diene • Catalyst not poisoned by • nitrogen functionality Kobayashi, S.; Ishitani, H., Araki, M.; Hachiya, I. Tetrahedron Lett. 1994, 35, 6325. Lanthanides: Chemistry and Use in Organic Synthesis; Kobayashi, S., Ed; Springer-Verlag: Berlin, 1999.

  13. 1,3-Dipolar Cycloaddition Sanchez-Blanco, A. I.; Gothelf, K. V.; Jørgensen, K. A. Tetrahedron Lett. 1997, 38, 7923. Kobayashi, S.; Kawamura, M. J. Am. Chem. Soc. 1999, 120, 5840.

  14. Overview • Historical Perspective • Asymmetric Cycloadditions • Multifunctional Asymmetric Catalysts • C-C Bond Formation • C-P Bond Formation • C-O Bond Formation • Conclusions/Future Directions

  15. Concept of Multifunctional Catalysis Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187. Shibasaki, M.; Kanai, M.; Matsunaga, S. Aldrichim. Acta2006, 39, 31.

  16. Preparation of Catalysts Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187. Shibasaki, M.; Kanai, M.; Matsunaga, S. Aldrichim. Acta2006, 39, 31.

  17. Asymmetric Nitro-Aldol Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187. Sasai, H.; Suzuki, T.; Itoh, N.; Arai, S.; Arai, T.; Shibasaki, M. J. Am. Chem. Soc. 1992, 114, 4418.

  18. Postulated Catalytic Cycle Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187. Sasai, H.; Suzuki, T.; Itoh, N.; Arai, S.; Arai, T.; Shibasaki, M. J. Am. Chem. Soc. 1992, 114, 4418.

  19. Tunability of Ln3+ Ionic Radius • 1st systematic study of its kind • Small changes (0.1 Å) cause • drastic differences Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187. Sasai, H.; Suzuki, T.; Itoh, N.; Arai, S.; Shibasaki, M. Tetrahedron Lett. 1993, 34, 2657.

  20. Concept of Direct Aldol Reaction Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187. Yoshikawa, N.; Yamada, Y. M. A.; Das, J.; Sasai, H.; Shibasaki, M. J. Am. Chem. Soc.1999, 121, 4168.

  21. Direct Aldol Reaction • Long reaction times • Excess amounts of ketone • High catalyst loading Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187. Yoshikawa, N.; Yamada, Y. M. A.; Das, J.; Sasai, H.; Shibasaki, M. J. Am. Chem. Soc.1999, 121, 4168.

  22. A Heteropolymetallic Catalyst • KOH formed in situ • Use of (R)-LPB ineffective Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187. Yoshikawa, N.; Yamada, Y. M. A.; Das, J.; Sasai, H.; Shibasaki, M. J. Am. Chem. Soc.1999, 121, 4168.

  23. Mechanistic Insights • kH/kD ~ 5 with d3-acetophenone • Rate independent of aldehyde • Coordination of aldehyde to La3+ • confirmed by NMR studies Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187. Yoshikawa, N.; Yamada, Y. M. A.; Das, J.; Sasai, H.; Shibasaki, M. J. Am. Chem. Soc.1999, 121, 4168.

  24. Application in Total Synthesis Yoshikawa, N.; Yamada, Y. M. A.; Das, J.; Sasai, H.; Shibasaki, M. J. Am. Chem. Soc.1999, 121, 4168.

  25. Michael Addition of Malonates Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187. Sasai, H.; Arai, T.; Satow, Y.; Houk, K. N.; Shibasaki, M. J. Am. Chem. Soc.1995, 117, 6194.

  26. Postulated Catalytic Cycle Sasai, H.; Arai, T.; Satow, Y.; Houk, K. N.; Shibasaki, M. J. Am. Chem. Soc.1995, 117, 6194. Lanthanides: Chemistry and Use in Organic Synthesis; Kobayashi, S., Ed; Springer-Verlag: Berlin, 1999.

  27. Enantiofacial Control pro-(R) Favored pro-(S) Disfavored + 4.9 kcal/mol (UFF) Sasai, H.; Arai, T.; Satow, Y.; Houk, K. N.; Shibasaki, M. J. Am. Chem. Soc.1995, 117, 6194. Rappé, A. K.; Casewit, C. J.; Colwell, K. S.; Goddard III, W. A.; Skiff, W. M. J. Am. Chem. Soc.1995, 114, 10024.

  28. NMR Studies Why LSB vs. LLB? • No coordination with LLB • LSB activates enone and • controls its direction • Size of coordination sphere • Difference in dihedral angles • of BINOL ligands Sasai, H.; Arai, T.; Satow, Y.; Houk, K. N.; Shibasaki, M. J. Am. Chem. Soc.1995, 117, 6194. Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187.

  29. Tunability of Alkali Metal Michael Addition Nitro-Aldol Sasai, H.; Arai, T.; Satow, Y.; Houk, K. N.; Shibasaki, M. J. Am. Chem. Soc.1995, 117, 6194. Shibasaki, M.; Sasai, H.; Arai, T.; Iida, T. Pure & Appl. Chem.1998, 70, 1027.

  30. Improved Catalyst Kim, Y. S.; Matsunaga, S.; Das, J.; Sekine, A.; Ohshima, T.; Shibasaki, M. J. Am. Chem. Soc.2000, 122, 6506.

  31. Overview • Historical Perspective • Asymmetric Cycloadditions • Multifunctional Asymmetric Catalysts • C-C Bond Formation • C-P Bond Formation • C-O Bond Formation • Conclusions/Future Directions

  32. Hydrophosphonylation of Imines Sasai, H.; Arai, S.; Tahara, Y.; Shibasaki, M. J. Org. Chem.1995, 60, 6656. Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187.

  33. Hydrophosphonylation of Imines Gröger, H.; Saida, Y.; Sasai, H.; Yamaguchi, K.; Martens, J.; Shibasaki, M. J. Am. Chem. Soc.1998, 120, 3089. Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187.

  34. Effectiveness of Cyclic Phosphites Maffei, M.; Buono, G. Tetrahedron 2003, 59, 8821. Schlemminger, I.; Saida, Y.; Gröger, H.; Maison, W.; Durot, N.; Sasai, H.; Shibasaki, M.; Martens, J. J. Org. Chem. 2000, 65, 4818.

  35. Proposed Catalytic Cycle Gröger, H.; Saida, Y.; Sasai, H.; Yamaguchi, K.; Martens, J.; Shibasaki, M. J. Am. Chem. Soc.1998, 120, 3089. Schlemminger, I.; Saida, Y.; Gröger, H.; Maison, W.; Durot, N.; Sasai, H.; Shibasaki, M.; Martens, J. J. Org. Chem. 2000, 65, 4818.

  36. Overview • Historical Perspective • Asymmetric Cycloadditions • Multifunctional Asymmetric Catalysts • C-C Bond Formation • C-P Bond Formation • C-O Bond Formation • Conclusions/Future Directions

  37. Epoxidation of Enones Nemoto, T.; Ohshima, T.; Yamaguchi, K.; Shibasaki, M. J. Am. Chem. Soc.2001, 123, 2725.

  38. Postulated Catalytic Cycle Nemoto, T.; Ohshima, T.; Yamaguchi, K.; Shibasaki, M. J. Am. Chem. Soc.2001, 123, 2725.

  39. Diversity in Catalysis Shibasaki, M.; Sasai, H.; Arai, T.; Iida, T. Pure & Appl. Chem.1998, 70, 1027. Shibasaki, M.; Yoshikawa, N. Chem. Rev. 2002, 102, 2187.

  40. Conclusions • Advantages of lanthanide catalysis • ‒ Tunability • ‒ Diversity of possible reactions • ‒ Water/air stable • ‒ Recyclable • Limitations • ‒ Long reaction times • ‒ High catalyst loading • ‒ Aggregation of complexes

  41. Future Directions • Increase efficiency of catalysts • Application in industry • Broaden the scope of substrates “These elements perplex us in our researches, baffle us in our speculations, and haunt us in our very dreams. They stretch like an unknown sea before us; mocking, mystifying and murmuring strange revelations and possibilities.” - Sir William Crookes (1887) Address to the Royal Society Aspinall, H. C. Chemistry of the f-Block Elements; Gordon and Breach: Amsterdam , 2001.

  42. Acknowledgements • Professor Richard Hsung • Hsung group members • Practice talk attendees • - John Feltenberger • - Kyle DeKorver • - BrittlandDeKorver • - Lauren Carlson • - Jenny Werness • - Aaron Almeida • - Kevin Williamson • - Dr. Yu Zhang • - Dr. Ryuji Hayashi • - Dr. Yu Tang - Ting Lu - Gang Li - Grant Buchanan - Yonggang Wei - Hongyan Li • Kat Myhre • Colleen Lohse

More Related