有机化学（浙江大学药学院）

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1、OrganicChemistry俞永平浙江大学药学院,1710yongpingyu@hotmail.com;Tel:87217325OrganicReactions,SynthesisThefirstorganicsynthesiswasaccomplishedbyFriedrichWohlerin1828AlkanesandCycloalkanesAlkanes:CycloalkanesAlkanesarecharacterizedbyageneralinertnesstomanychemicalreagentsWhenheat

2、ed,alkanescanreactwithchlorine,bromine.SynthesisofalkanesandcycloalkanesA:HyrogenationofalkenesandalkynesGeneralReaction:SynthesisofalkanesandcycloalkanesSpecificexamplesSynthesisofalkanesandcycloalkanesSynthesisofalkanesandcycloalkanesB:ReductionofAlkylHalidesGeneral

3、Reaction:Zincatomstransferelectronstocarbonatomofalkylhalide:SynthesisofalkanesandcycloalkanesSpecificExamplesSynthesisofalkanesandcycloalkanesAlyklationofterminalalkynesGeneralreactionSpecificreactionSynthesisofalkanesandcycloalkanesSpecificreactionAlkylHalides:Nucle

4、ophilicSubstitutionandEliminationReactionsWhendoesthecarbon-halogenbondbreak?Doesitbreakatthesametimethatthenewbondbetweenthenucleophileandthecarbonforms?AMechanismfortheSN2ReactionReaction:Mechanism:ThestereochemistryofSN2ReactionThenucleophileattacksfromthebackside,

5、thatis,fromthesidedirectlyoppositetheleavinggroup.Thismodeofattackcausesachangeintheconfiguration.ThestereochemistryofSN2ReactionAMechanismfortheSN1ReactionReactions:Step1:AMechanismfortheSN1ReactionStep2:Step3:ThestereochemistryofSN1reactionsReactionsthatinvolveracem

6、ization:FactorsaffectingtheratesofSN1andSN2reactionThestructureofthesubstrateTheconcentrationandreactivityofthenucleophileTheeffectofthesolventThenatureoftheleavinggroupTheeffectofthestructureofthesubstrateSN2ReactionsSimplyalkylhalidesshowthefollowinggeneralorderofre

7、activityinSN2reactions:(stericeffect)Methyl>primary>secondary>>(tertiary-unreactive)FactorsfavoringSN1versusSN2reactionsFactorSN1SN2Substrate3oMethyl>1o>2oNucleophileWeakLewisBasStrongLewisbaseSolventPolarprotic(alcohols,H2O)Polaraprotic(DMF,DMSO)LeavinggroupI->Br->Cl

8、->F-ForbothSN1andSN2FunctionalgrouptransformationsusingSN2reactionsEliminationreactions(dehydrohalogenations)ofalkylhalidesA