1 / 43

Chapter 12 Molecular Rearrangements

Chapter 12 Molecular Rearrangements. PRODUCER ：张文勤. I Classification of Rearrangement Reactions ( ) II Nucleophilic Rearrangement ( ) 1 Wagner-Meerwein rearrangement ( ) 2 Pinacolic Rearrangement ( ) 3 α-ethandione Rearrangement ( ) 4 Beckmann Rearrangement ( )

marvin-kirby
Télécharger la présentation

Chapter 12 Molecular Rearrangements

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. Chapter 12 Molecular Rearrangements PRODUCER：张文勤 I Classification of Rearrangement Reactions() II Nucleophilic Rearrangement () 1 Wagner-Meerwein rearrangement() 2 Pinacolic Rearrangement () 3 α-ethandione Rearrangement () 4 Beckmann Rearrangement () 5 Baeyer-Villiger Rearrangement () III Electrophilic Rearrangement() 1 favorskii Rearrangement 2 Stevens Rearrangement 3 Wittig Rearrangement 4 Fries Rearrangement IV Radical Rearrangement

  2. I Classification of Rearrangement Reactions Molecular Rearrangements:it refers those reactions in which the carbon skeleton or the position of functional group changed.

  3. Usually the rearrangement was classified by the electron property of the moving group, such as Nucleophilic rearrangement, Electrophilic rearrangement, Radical rearrangement, etc. Nucleophilic rearrangement

  4. Electrophilic rearrangement Radical rearrangement

  5. II Nucleophilic Rearrangement 1 Wagner-Meerwein rearrangement ( Carbon cation rearrangement )

  6. Stable cation Stable cation

  7. 2 Pinacolic Rearrangement

  8. The stable cation formed superior Phenyl group move first

  9. Phenyl with electron donor group move first

  10. Under HNO2, the amino alcohol rearranges as that of pinacol

  11. 3 α-Ethandione Rearrangement

  12. α-Ethandione with α- hydrogen will proceed condensation

  13. If NaOH was replaced by NaOMe or t-BuONa, α-hydroxycarboxyester will be produced Usually, ethyloxy anion acts as a reduction reagent.

  14. 4 Beckmann Rearrangement The group opposite to hydroxy will shift

  15. The shift will keep the stereostructure of chiral center

  16. 5 Baeyer-Villiger Rearrangement

  17. Group moved as the following order: tertiary alkyl＞aryl＞H＞secondary alkyl ＞primary alkyl＞methyl

  18. The cumene hydroperoxide rearrangement is quite resemble the Baeyer-Villiger Rearrangement

  19. Important industrial reaction for manufacturing phenol and acetone

  20. III Electrophilic Rearrangement Electrophilic rearrangement is not so common as nucleophilic rearrangement The transition state is:

  21. 1 Favorskii Rearrangement

  22. Mechanism of Favorskii Rearrangement

  23. For asymmetric cycloprapanone, the stable anion form dominantly

  24. Different α- chloroketone form same rearrangement product:

  25. Intramolecular SN2 attack(structure maintaining):

  26. 2 Stevens Rearrangement Structure maintaining

  27. The sulfonium cation does the same

  28. Sommelet Rearrangement

  29. 3 Wittig Rearrangement

  30. 4 Fries Rearrangement

  31. IV Radical Rearrangement

  32. Usually the aryl, alkenyl and acetoxy can shift

More Related