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1、JournalofMolecularStructure:THEOCHEM908(2009)26–30ContentslistsavailableatScienceDirectJournalofMolecularStructure:THEOCHEMjournalhomepage:www.elsevier.com/locate/theochemRingexpansionof2-chloromethylpyrrolidineorazetidine:Comparedtheoreticalinvestigationa,*bFrançoisCouty,MikhailKletsk
2、iiaInstitutLAVOISIER,UMRCNRS8180,UniversitédeVersailles,45,AvenuedesEtats-Unis,78035VersaillesCédex,FrancebDepartmentofChemistry,SouthernFederalUniversity,7,ZorgeSt.,344090Rostov-on-Don,RussianFederationarticleinfoabstractArticlehistory:DFTcalculationwereperformedinordertosimulatetheri
3、ngenlargementofN-isopropyl-2-chloromethylReceived24March2009pyrrolidineandazetidineintothecorresponding3-chloropiperidineand3-chloropyrrolidine,respec-Receivedinrevisedform27April2009tively.TheseringenlargementsareprototypesofreactionsthathavefoundgrowingapplicationsinAccepted29April20
4、09thesynthesisofnitrogenheterocycles.BothcalculationswereconductedingasphaseandinDMSO,usingAvailableonline7May2009apolarizablecontinuummodel.Ingasphase,theseringenlargementswerefoundtobesynchronousreactions,withasingletransitionstate,butinDMSO,significantdecreaseofenergybarrierisobserve
5、d,Keywords:andthetworeactionsdiffernowtoalargeextent,sincetheazetidinerearrangesthroughastrained1-Azetidinesazonia-bicyclo[2.1.0]pentaneintermediate50,whilethepyrrolidinestillrearrangesinasinglestepPyrrolidinesAzetidiniumionsprocess.RingexpansionÓ2009ElsevierB.V.Allrightsreserved.1.Int
6、roductiontions,littleisknownabouttheintimatemechanismofthesecondrearrangement.Surprisingly,noneofthesereactionshaveyetbeenRingenlargementof2-chloromethylpyrrolidine1into3-studiedinsilico.Therefore,consideringthesyntheticimportancechloro-piperidine3isavenerablereactionthatwasfirstreporte
7、doftheseringexpansionsandthelackofaccuratekineticdataforbyFuson[1].Ithasbeenproposedthroughaccurateexperimentaltheazetidinecase,wehaveundertakenaDFTsimulationofbothdataandkineticmeasurementsfromHammeretal.[2]thatthisrearrangements,startingfromN-isopropylderivatives1and4.reactionstake
