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TetrahedronLettersTetrahedronLetters45(2004)1441–1444Arobustpalladium-catalyzedcyanationprocedure:beneficialeffectofzincacetateRamakrishnanChidambaram*ProcessResearchandDevelopment,Bristol–MyersSquibb,NewBrunswick,NJ08908,USAReceived1December2003;revised9December2003;accepted9December2003Abstract—ConditionsthatensureamorereproduciblePd(0)-mediatedproceduretoconvertarylbromidestoarylcyanideshavebeendevelopedthatentailtheuseofzincdusttokeepthePdinthezerooxidationstateandzincacetatetoensurehighcatalyticactivity.Thisprocedureisapplicabletoawiderangeofsubstratesandobviatestheneedforstringentremovalofoxygenfromthereactionmedium.Ó2003ElsevierLtd.Allrightsreserved.Averyimportantandusefulreactioninorganicsyn-Asexpected,whentheDMFwassaturatedwithoxygen,thesisistheconversionofanarylbromideorchloridetotherewasabsolutelynoconversionofIintoII.anarylcyanide;1severalproceduresinvolvingtheuseoftransitionmetalsareavailable.2Unfortunately,mostofThisimplicatedoxygenasthemainsourceindeactiva-theseproceduresrequirehightemperatures( 120–tionofthecatalyst,resultinginlowerconversion.4Since140°C),andmoreimportantly,thereactionstendtobeoxygenmostlikelyoxidizestheactivepalladium(0)capricious.speciestoapalladium(II)species,theinsituuseofareductantmightreducethepalladium(II)backtotheOureffortsweredirectedtowardsfindingageneralandpalladium(0)speciesandreintroduceitintothecatalyticscalableproceduretoconvertsubstitutedbromoacet-cycle.SincezinchasbeenusedincyanationreactionstoanilideItothecorrespondingproprietarycyanocom-reducepalladium(II)species,3b;5weadded3–4mol%poundII.Thetwomostrecentlyreportedsystemsforzincdusttoourcyanationreactionandobtainedsuchaconversionare:excellentconversion(>99areapercent)ofIintoIIwithouttheneedtodeoxygenatetheDMF.Thecya-(a)Pd(OAc)2asthecatalyst,dppeasaligandandacet-nationprocedureusingzincdustwasthensuccessfullyonecyanohydrinasthecyanidesource2andscaleduptoproducemulti-kilogramquantitiesofII.0(b)Pd2(dba)3incombinationwithdppf[1,1-bis(diph
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