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1、Chapter8MolecularRearrangementsIClassificationofRearrangementReactionsIINucleophilicRearrangement1Wagner-Meerweinrearrangement2PinacolicRearrangement3α-ethandioneRearrangement4BeckmannRearrangement5Baeyer-VilligerRearrangementIIIElectrophilicRearrangement1Fa
2、vorskiiRearrangement2StevensRearrangement3WittigRearrangement4FriesRearrangementIVRadicalRearrangementIClassificationofRearrangementReactionsMolecularRearrangements:itrefersthosereactionsinwhichthecarbonskeletonorthepositionoffunctionalgroupchanged.Usuallyth
3、erearrangementwasclassifiedbytheelectronpropertyofthemovinggroup,suchasNucleophilicrearrangement,Electrophilicrearrangement,Radicalrearrangement,etc.NucleophilicrearrangementElectrophilicrearrangementRadicalrearrangementIINucleophilicRearrangement1Wagner-Mee
4、rweinrearrangement(Carboncationrearrangement)StablecationStablecationDemyanovrearrangement2PinacolicRearrangement?ThestablecationformedsuperiorPhenylgroupmovefirstGroupmovedasthefollowingorder:aryl>alkyl>HUnderHNO2,theaminoalcoholrearrangesasthatofpinacolQue
5、stionAnswer3α-EthandioneRearrangementα-Ethandionewithα-hydrogenwillproceedcondensationIfNaOHwasreplacedbyNaOMeort-BuONa,α-hydroxycarboxyesterwillbeproducedUsually,ethyloxyanionactsasareductionreagent.4BeckmannRearrangementThegroupoppositetohydroxywillshiftTh
6、eshiftwillkeepthestereostructureofchiralcenter5Baeyer-VilligerRearrangementGroupmovedasthefollowingorder:tertiaryalkyl>aryl>H>secondaryalkyl>primaryalkyl>methylThecumenehydroperoxiderearrangementisquiteresembletheBaeyer-VilligerRearrangementHydroperoxiderear
7、rangementImportantindustrialreactionformanufacturingphenolandacetoneIIIElectrophilicRearrangementElectrophilicrearrangementisnotsocommonasnucleophilicrearrangementThetransitionstateis:1FavorskiiRearrangementMechanismofFavorskiiRearrangementForasymmetriccyclo
8、prapanone,thestableanionformdominantlyDifferentα-chloroketoneformsamerearrangementproduct:IntramolecularSN2attack(structuremaintaining):2StevensRearrangementStructuremaintainingThesulfoniumcatio