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A Report Start from DABCO (16 referrences )

A Report Start from DABCO (16 referrences ). Xiao-le Zhou 2013-4-27. Start of the Report. A reaction from the total synthesis of ( + )- Bisabosqual A. C. W. am Ende , Z. Zhou, K. A.Parker J. Am. Chem. Soc. 2013 ,  135 , 582-585. Mechanism of the reaction.

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A Report Start from DABCO (16 referrences )

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  1. A Report Start from DABCO (16 referrences) Xiao-le Zhou 2013-4-27

  2. Start of the Report • A reaction from the total synthesis of (+)-Bisabosqual A C. W. am Ende, Z. Zhou, K. A.Parker J. Am. Chem. Soc. 2013, 135, 582-585

  3. Mechanism of the reaction Y. L. Shi, M. Shi. Org. Lett. 2005, 7, 3057-3060 G.L. Zhao, Y. L. Shi, M. Shi. Org. Lett. 2005, 7, 4527-4530

  4. Start of the Report asymmetric tertiary amine asymmetry!

  5. Start of the Report Then a substituted DABCO come into my heart, like this: It’s an interesting molecure, since: 1: It has 2 activate sites, both N1 and N2; 2: The stereochemistry of 2 N atoms are blocked hence they’re chiral N atoms.

  6. The Interests of the Molecule efficiency Double activate core Blocked stereochemistry selectivity

  7. Efficiency How does a reaction occur? 1: Appropriate direction; 2: Efficient energy. A Appropriate direction: 1 reactant approaches the other within a certain angular(w). w(A) = 2w(B) Assume the relationship of the rate (r) and (w) is r = f(w) Then r(A) = f[w(A)] = f[2w(B)] If the related function f() involves an item of kwn r(A) = k·r(B)·2n + M VS B

  8. Efficiency What accounts the conclusion? Another chance to accelerate the reaction for the second time! 2 mols one site catalyst !!! 1 mol 2 sites catalyst >> Senior Wang’s advice: Bimetallic catalysts Limited to : Homonuclear bimetallic systems Tethered bimetallic systems Covalent tethered ones.

  9. Bimetallic complexes Catalyzed cyclopentene oxide opening reactions L. E. Martinez, J. L. Leighton, D. H. Carsten, E. N. Jacobsen. J. Am. Chem. Joc. 1995,117, 5897-5898 Second order dependence of catalyst Intermolecular pathway K. B. Hansen, E. N. Jacobsen, et al. J. Am. Chem. Soc. 1996,118, 10924-10925

  10. Table 1. Rate constans and ee% data for the opening of cyclopentene oxide catalyzed by (salen)Cr-N3 complexes Emerging intramolecular pathway Enhanced intermolecular pathway R. G. Konsler, J. Karl, E. N. Jacobsen. J. Am. Chem. Soc. 1998, 120, 10780-10781

  11. Hydrolytic Kinetic Resolution of Terminal Epoxides M. Tokunaga, J. F. Larrow, F. Kakiuchi, E. N. Jacobsen. Science 1997, 277,936-938

  12. R Breinbauer, E. N. Jacobsen. Angew. Chem. Int. Ed. 2000,39,3604-3607

  13. R Breinbauer, E. N. Jacobsen. Angew. Chem. Int. Ed. 2000,39,3604-3607

  14. A Similar Reaction with [(Salen)Al] Complexes G. M. Sammis, E. N. Jacobsen. J. Am. Chem. Soc. 2003, 125, 4442-4443 C. Mazet, E. N. Jacobsen. Angew. Chem. Int. Ed. 2008, 47, 1762-1765

  15. A Similar Reaction with [(salen)Al] complexes G. M. Sammis, E. N. Jacobsen. J. Am. Chem. Soc. 2003, 125, 4442-4443 C. Mazet and E. N. Jacobsen. Angew. Chem. Int. Ed. 2008, 47, 1762 –1765

  16. Figure 2. Reactivity of {(salen)Al} complexes in the catalytic conjugate cyanation of imid. □ 1(90% ee), + 2c,d (95% ee), △ 2e (95% ee), ○ 2 f,g (93% ee). C. Mazet and E. N. Jacobsen. Angew. Chem. Int. Ed. 2008, 47, 1762 –1765

  17. Reconsideration of the Bimetallic Systems Carefully Table 1. Rate constans and ee% data for the opening of cyclopentene oxide catalyzed by (salen)Cr-N3 complexes Emerging intramolecular pathway Enhanced intermolecular pathway Multi-nuclear Multi-coordination Multi reactive sites effect How does this occurs?

  18. So What? • Multi core or multi reactive sites means a second acceleration of the catalysts. • This could be used to the non-interfering cooperating catalysts, since the cooperation of the catalysts could be reinforced. • Kinetics should also taken good consideration, cause it could enhance the enantioselectivity for some time, owing to the improved activity of the catalysts.

  19. The Interests of the Molecule efficiency Double activate core Blocked stereochemistry selectivity

  20. Selectivity • 3 modifiable C linked to N • C-2 symmetric skeleton • Overmuch chiral centers • Difficult-synthesized skeleton Cinchona Alkaloids • Readily available natural products • Easily modified • Multi-function molecule • Focus on base catalyzed conjugate addition

  21. Addition of Aromatic Thiols to Conjugated Cycloalkenones H. Hiemstra, H.Wynberg. J. Am. Chem. Soc. 1981,103, 417-430

  22. Electrostatic force π stacking Hbonding overall interactionconfirm the configuration

  23. Addition of 2-Nap Thiol to Conjugated Cycloalkenones P. McDaid, Y. Chen, L.Deng. Angew. Chem. Int. Ed. 2002, 41, 338-340 Conjugate Additions Catalyzed by Cinchona Alkaloids H. Li, Y. Wang, L. Tang, L. Deng. J. Am. Chem. Soc.2004,126,9906-9907 H. Li, Y. Wang, L. Tang, F. Wu, X. Liu, C Guo, B. M. Foxman, L. Deng. Angew. Chem. Int. Ed. 2005,44, 105 –108

  24. Acetyl Acetone Like Substrates Conjugate Addition to Alkynones M. Bella, K. A. JørgensenJ. Am. Chem. Soc. 2004,126, 5672-5673 Cascade Conjugate Addition????

  25. Acknowledge Thanks a lot to senior Pu-sheng Wang for his advice for my literature report, and his help on my works and study.

  26. Thank you for your attention!

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