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Asymmetric Tandem Epoxidation – [4+3] Cycloaddition of Allenamides

Asymmetric Tandem Epoxidation – [4+3] Cycloaddition of Allenamides. Livia Aumand February 3, 2005. [4+3] Cycloaddition. [4+3] Cycloaddition. [4+3] Cycloaddition. Indirect [4 + 3] Cycloaddition of Rhodium Vinyl Carbenoids. Davies, H.M.L. et al. J. Am. Chem. Soc . 1998 , 120 , 3326.

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Asymmetric Tandem Epoxidation – [4+3] Cycloaddition of Allenamides

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  1. Asymmetric Tandem Epoxidation – [4+3] Cycloaddition of Allenamides Livia Aumand February 3, 2005

  2. [4+3] Cycloaddition

  3. [4+3] Cycloaddition

  4. [4+3] Cycloaddition

  5. Indirect [4 + 3] Cycloaddition of Rhodium Vinyl Carbenoids Davies, H.M.L. et al. J. Am. Chem. Soc. 1998, 120, 3326.

  6. Indirect [4+3] Cycloaddition of Pd-Trimethylmethylene (TMM) Complex Chan, D.T. In Cycloaddition Reactions in Organic Synthesis; Kobayashi, S., Jorgensen, K.A., Eds.; Wiley-VCH: Weinheim, 2002, pp 57-84.

  7. Indirect [4+3] Cycloaddition of Pd-Trimethylmethylene (TMM) Complex Chan, D.T. In Cycloaddition Reactions in Organic Synthesis; Kobayashi, S., Jorgensen, K.A., Eds.; Wiley-VCH: Weinheim, 2002, pp 57-84.

  8. Indirect [4+3] Cycloaddition of Pd-Trimethylmethylene (TMM) Complex Chan, D.T. In Cycloaddition Reactions in Organic Synthesis; Kobayashi, S., Jorgensen, K.A., Eds.; Wiley-VCH: Weinheim, 2002, pp 57-84.

  9. Indirect [4+3] Cycloaddition of Pd-Trimethylmethylene (TMM) Complex Chan, D.T. In Cycloaddition Reactions in Organic Synthesis; Kobayashi, S., Jorgensen, K.A., Eds.; Wiley-VCH: Weinheim, 2002, pp 57-84.

  10. [4+3] Cycloaddition of Pd-Trimethylmethylene (TMM) Complex Trost, B.M. and D.T. MacPherson. J. Am. Chem. Soc. 1987, 109, 3483.

  11. [4+3] Cycloaddition of Allylic Cation Noyori, R.et al. J. Am. Chem. Soc. 1971, 93, 1272.

  12. [4+3] Cycloaddition of Oxyallyl Cation

  13. Frontier Molecular Orbital Theory in [4+3] Cycloaddition of Oxyallyl Cation

  14. Frontier Molecular Orbital Theory in [4+3] Cycloaddition of Oxyallyl Cation

  15. The Oxyallyl Cation: Valence Tautomeric Triad Chan, T.H. and B.S. Ong Tetrahedron1980, 36, 2269.

  16. The Oxyallyl Cation Rigby, J.H. et al. Org. React. 1997, 51, 351.

  17. [4+3] Cycloaddition of Oxyallyl Cation: Mechanistic Spectrum

  18. [4+3] Cycloaddition of Oxyallyl Cation: Mechanistic Spectrum

  19. Concerted vs Stepwise Mechanism D.I. Rawson et al. J. Am. Chem. Soc. 1979, 101, 1786.

  20. Perturbation Theory

  21. Klopman-Salem Equation 1st term: Filled-filled orbital interaction  Ignore 2nd term: Coulombic interaction  Important for charged / polar molecules 3rd term: Filled-unfilled orbital interactions  HOMO and LUMO Fleming, I. Frontier Orbitals and Organic Chemical Reactions. John Wiley & Sons: New York, 1976.

  22. Klopman-Salem Equation 1st term: Filled-filled orbital interaction  Ignore 2nd term: Coulombic interaction  Important for charged / polar molecules 3rd term: Filled-unfilled orbital interactions  HOMO and LUMO Fleming, I. Frontier Orbitals and Organic Chemical Reactions. John Wiley & Sons: New York, 1976.

  23. Klopman-Salem Equation 1st term: Filled-filled orbital interaction  Ignore 2nd term: Coulombic interaction  Important for charged / polar molecules 3rd term: Filled-unfilled orbital interactions  HOMO and LUMO Fleming, I. Frontier Orbitals and Organic Chemical Reactions. John Wiley & Sons: New York, 1976.

  24. Simplified Klopman-Salem Equation

  25. Simplified Klopman-Salem Equation

  26. Simplified Klopman-Salem Equation

  27. Simplified Klopman-Salem Equation

  28. Simplified Klopman-Salem Equation

  29. Simplified Klopman-Salem Equation

  30. Simplified Klopman-Salem Equation

  31. Klopman-Salem Equation and Mechanism of [4 + 3] Cycloaddition

  32. Klopman-Salem Equation and Mechanism of [4 + 3] Cycloaddition

  33. Klopman-Salem Equation and Mechanism of [4 + 3] Cycloaddition

  34. Klopman-Salem Equation and Mechanism of [4 + 3] Cycloaddition

  35. Klopman-Salem Equation and Mechanism of [4 + 3] Cycloaddition

  36. Klopman-Salem Equation and Mechanism of [4 + 3] Cycloaddition

  37. Stereoselectivity of [4+3] Cycloaddition of Oxyallyl Cation Chan, T.H.; Ong, B.S. Tetrahedron1980, 36, 2269. D.I. Rawson et al. J. Am. Chem. Soc. 1979, 101, 1786.

  38. Stereoselectivity of [4+3] Cycloaddition of Oxyallyl Cation Chan, T.H.; Ong, B.S. Tetrahedron1980, 36, 2269. D.I. Rawson et al. J. Am. Chem. Soc. 1979, 101, 1786.

  39. Stereoselectivity of [4+3] Cycloaddition of Oxyallyl Cation Chan, T.H.; Ong, B.S. Tetrahedron1980, 36, 2269. D.I. Rawson et al. J. Am. Chem. Soc. 1979, 101, 1786.

  40. Stereoselectivity of [4+3] Cycloaddition of Oxyallyl Cation Chan, T.H.; Ong, B.S. Tetrahedron1980, 36, 2269. D.I. Rawson et al. J. Am. Chem. Soc. 1979, 101, 1786.

  41. Stereoselectivity of Concerted [4+3] Cycloaddition of Oxyallyl Cation Hoffmann, H.M.R. Tetrahedron1983, 23, 1.

  42. Concerted Process: endo vs exo Selectivity Rigby, J.H. et al. Org. React. 1997, 51, 351.

  43. Oxyallyl Cations with Reduced Electrophilicity

  44. Oxyallyl Cations with Reduced Electrophilicity

  45. Heteroatom-Stabilized Oxyallyl Cations • Less electrophilic than oxyallyl cation • Favour concerted [4+3] • endo selective endo

  46. Nitrogen-Substituted Oxyallyl Cations Trivalent nitrogen atom  ASYMMETRIC [4+3] cycloaddition Myers, A.G. & J.K. Barbay Org. Lett. 2001, 3, 425.

  47. Nitrogen-Substituted Oxyallyl Cations Trivalent nitrogen atom  ASYMMETRIC [4+3] cycloaddition Myers, A.G. & J.K. Barbay Org. Lett. 2001, 3, 425.

  48. Tandem Epoxidation – [4+3] Cycloaddition of Allenamides Allenamides: • Electron-deficient variants of allenamines • More stable, storable, and easier to handle Xiong, H. J. Am. Chem. Soc. 2001, 123, 7174.

  49. Synthesis of Allenamides: A Fortuitous Accident! • Different bases, solvents, temperatures, times  allenamide only Landor, S. R. (Ed.) The Chemistry of the Allenes. 1982, 1, 168. Wei, L. et al. Tetrahedron2001, 57, 459.

  50. Synthesis of Allenamides: A Fortuitous Accident! • Different bases, solvents, temperatures, times  allenamide only Landor, S. R. (Ed.) The Chemistry of the Allenes. 1982, 1, 168. Wei, L. et al. Tetrahedron2001, 57, 459.

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