1 / 94

高等有机化学 —— 反应机理

高等有机化学 —— 反应机理. 第四课 周环反应. 1 、基础知识. A pericyclic reaction is a reaction in which bonds are formed or broken at the termini of one or more conjugated systems. The electrons move around in a circle, all bonds are made and broken simultaneously, and no intermediates intervene. Typical reactions

zephania-gentry
Download Presentation

高等有机化学 —— 反应机理

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. 高等有机化学——反应机理

  2. 第四课 周环反应

  3. 1、基础知识 A pericyclic reaction is a reaction in which bonds are formed or broken at the termini of one or more conjugated systems. The electrons move around in a circle, all bonds are made and broken simultaneously, and no intermediates intervene. • Typical reactions • Regioselectivity • Stereoselectivity • Stereospecificity

  4. 4.1.1 Classes of Pericyclic Reactions • Electrocyclic reactions (ring openings or ring closings), • Cycloadditions • Sigmatropic rearrangements • Ene reactions.

  5. Electrocyclic reactions

  6. Cycloadditions

  7. Cycloadditions Cheletropic reactions

  8. Sigmatropic rearrangements

  9. Sigmatropic rearrangements

  10. Sigmatropic rearrangements

  11. Ene Reaction

  12. 四种周环反应总结

  13. 立体专一性

  14. Polyene MOs Woodward–Hoffmann rules

  15. Polyene MOs

  16. Polyene MOs

  17. Polyene MOs

  18. 2、电环化反应 2.1、典型反应

  19. 2.1、典型反应

  20. 2.1、典型反应

  21. 2.1、典型反应

  22. 练习4.1

  23. 2.1、典型反应

  24. 2.1、Favorskii rearrangement

  25. 2.1、Favorskii rearrangement

  26. 练习

  27. 练习

  28. 4.2.2 Stereospecificity

  29. 1,3,5-hexatrienes

  30. 偶——热——顺 奇——热——反 偶——光——反 奇——光——顺

  31. The Woodward–Hoffmann rules apply only to concerted, pericyclic reactions. • A reaction can be forced to proceed through the higher energy TS if the lower energy one is raised prohibitively high in energy by geometric constraints.

  32. 4.2.3 Stereoselectivity

  33. 4.3 Cycloadditions 4.3.1 Typical Reactions 4.3.1.1 The Diels–Alder Reaction

More Related