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1、j794Microwave-AcceleratedHomogeneousCatalysisinWaterLukeR.OdellandMatsLarhed4.1IntroductionTheadvancementsinmicrowave-assistedmetalcatalysisinneatwaterhavealreadybeenremarkableinmanyways,afactthatisequallyvalidfortheactualchemicalprogressmadeandforthesheernumberofrece
2、ntpublications[1].Fiveyearsagoitwaspossibletoincludealltheliteratureintheareawithinthescopeofafewpages.In2007,therangeofinvestigatedtransformationsandthenumberofexamplesmakeitdifficulteventoincludeallexamplesinabookchapter[1].Thismini-reviewattemptstogiveanoverviewofmi
3、crowave-promotedmetal-catalyzedhomogeneoustransfor-mationsinneatwater,providingapersonalselectionofbothpioneeringandrecentlypublishedwork.Coveredareasincludecross-couplings,Heckreactions,carbonyla-tions,Sonogashirareactions,nucleophilicsubstitutionsandsomeadditionaltr
4、ans-formations.Itisnotablethatallavailablepublishedexampleswereconductedonthelaboratoryscale.Afterabriefbackgroundonmicrowaves[2–4],waterasreactionmedium[5]andtransitionmetalcatalysis[6],wepresentpreparativeexamplesanddiscusstheimpactandfuturepotentialinbothcatalysisa
5、ndsustainablechemistry[7,8].4.1.1MicrowaveHeatingInprinciple,allmetal-catalyzedorganictransformationsrequireaninputofenergytoproceedatausefulrate.Inthecorrectamountandintherightform,energydrivesthecatalyticcycleforward,providingthedesiredproductwithhighselectivityandi
6、nhighyield.Inthewrongamountorinthewrongform,energycaninsteadcompletelyinhibitthecatalyticprocess[9,10].Hencetheregulationoftheenergyinputandthechoiceoftheenergysourceareofvitalimportanceinhomogeneouscatalysis.Amongtheavailablealternatives,microwaveirradiationhasahugep
7、otentialtoprovidecontrolledenergydirectlytothemoleculesofinterest[10].GreenCatalysis,Volume1:HomogeneousCatalysis.EditedbyRobertH.CrabtreeCopyrightÓ2009WILEY-VCHVerlagGmbH&Co.KGaA,WeinheimISBN:978-3-527-32496-580j4Microwave-AcceleratedHomogeneousCatalysisinWaterMicrow
8、avesareabletoheatareactionmixturebytwogeneralmechanisms,dipolarpolarizationandionicconductance[2–4].Allnon-crystallinesolids