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1、DOI10.1515/hf-2013-0126 Holzforschung2014;68(4):369–375DaisukeAndo*,ToshiyukiTakanoandFumiakiNakatsuboMulti-stepdegradationmethodforβ-O-4linkagesinlignins:α-TSAmethod.Part1:Reactionofnon-phenolicdimericβ-O-4modelcompoundAbstract:Theα-TSAmethodhasbeendevel
2、opedforthebasedonthereactivityofbenzyliccations.Inparticular,cleavageofβ-O-4linkagesinlignin.Itconsistsofthreemildlignindegradationmethodswithoutsidereactionssteps:(1)thioetherificationatα-positionofβ-O-4sub-areneeded.structures,(2)sulfonylation,and(3)mild
3、alkalitreat-Recently,thenovelβ-O-4cleavagemethod(γ-TTSAmentoftheα-sulfonederivative.Themethodwastestedmethod)wasdeveloped(Andoet al.2012,2013a,b),onanonphenolicdimericβ-O-4ligninmodelcompound,inthecourseofwhichtheetherlinkagescleavedbynamelyon4-benzyloxy-3
4、-methoxyphenylglycerol-β-β-eliminationofγ-sulfoneligninderivativesundermildguaiacylether.Itdemonstratedthatthemildalkalidegra-conditions.Thekeytothisreactionwastheassistanceofdationoftheα-sulfonederivativeproceedsefficiently,i.e.,theneighbouringsulfonylgro
5、upattheγ-positionforthetheelectron-withdrawingsulfonegroupatα-positioncon-ethercleavage.However,intheβ-O-4substructurewithtributestothecleavageoftheβ-O-4linkageinthesameacylgroupatγ-position,thesulfonegroupcannotbeintro-mechanismasthatintheγ-TTSAmethod.duc
6、edandtheethercleavageimpeded.Theintroductionofsulfonylgroupattheα-positionwouldbeanalternativeKeywords:α-TSAmethod,β-elimination,β-O-4linkage,andtherewasevidencethatthisapproachwaspromisingcleavage,lignin,lignindegradation(Forzeliuset al.1963;JerkemanandLi
7、ndberg1964;Ljung-grenet al.1983),i.e.,theα-sulfonylgroupalsoactivatestheβ-elimination,sothattheE1cBtypereactioncantake*Correspondingauthor:DaisukeAndo,DivisionofForestandplace.Nevertheless,theintroductionofsulfonegroupinBiomaterialsScience,GraduateSchoolof
8、Agriculture,KyotoUniversity,Kitashirakawa-oiwakechoSakyo-ku,Kyoto,606-8502,theα-positionisnotquantitative.Forexample,theyieldJapan,Phone:+81-75-753-6256,Fax:+81-75-753-6300,wasonly51%inthecaseofthesimplemodel