Chapter 12 Molecular Rearrangements,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,PRODUCER：张文勤,I Classification of Rearrangement Reactions,Molecular Rearrangements:it refers those reactions in which the carbon skeleton or the position of functional group changed.,Usually the rearrangement was classified by the electron property of the moving group, such as Nucleophilic rearrangement, Electrophilic rearrangement, Radical rearrangement, etc.,Nucleophilic rearrangement,Electrophilic rearrangement,Radical rearrangement,II Nucleophilic Rearrangement,1 Wagner-Meerwein rearrangement( Carbon cation rearrangement ),Stable cation,,Stable cation,,2 Pinacolic Rearrangement,The stable cation formed superior,Phenyl group move first,Phenyl with electron donor group move first,Under HNO2, the amino alcohol rearranges as that of pinacol,3 α-Ethandione Rearrangement,α-Ethandione with α- hydrogen will proceed condensation,If NaOH was replaced by NaOMe or t-BuONa, α-hydroxycarboxyester will be produced,Usually, ethyloxy anion acts as a reduction reagent.,4 Beckmann Rearrangement,The group opposite to hydroxy will shift,The shift will keep the stereostructure of chiral center,5 Baeyer-Villiger Rearrangement,Group moved as the following order: tertiary alkyl＞aryl＞H＞secondary alkyl ＞primary alkyl＞methyl,The cumene hydroperoxide rearrangement is quite resemble the Baeyer-Villiger Rearrangement,Important industrial reaction for manufacturing phenol and acetone,III Electrophilic RearrangementElectrophilic rearrangement is not so common as nucleophilic rearrangement,The transition state is:,1 Favorskii Rearrangement,Mechanism of Favorskii Rearrangement,For asymmetric cycloprapanone, the stable anion form dominantly,Different α- chloroketone form same rearrangement product:,Intramolecular SN2 attack(structure maintaining):,2 Stevens Rearrangement,Structure maintaining,The sulfonium cation does the same,Sommelet Rearrangement,3 Wittig Rearrangement,4 Fries Rearrangement,IV Radical Rearrangement,Usually the aryl, alkenyl and acetoxy can shift,。