資源描述：
《(2007acie)(R)Recent advances in asymmetric phase-transfer catalysis.pdf》由會員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在學(xué)術(shù)論文-天天文庫。
1、ReviewsK.MaruokaandT.OoiDOI:10.1002/anie.200601737AsymmetricSynthesisRecentAdvancesinAsymmetricPhase-TransferCatalysisTakashiOoiandKeijiMaruoka*Keywords:asymmetricsynthesis·chiraloniumsalts·crowncompounds·enantioselectivity·phase-transfercatalysisAngewandteChemie4222www.an
2、gewandte.org2007Wiley-VCHVerlagGmbH&Co.KGaA,WeinheimAngew.Chem.Int.Ed.2007,46,4222–4266AngewandtePhase-TransferCatalysisChemieTheuseofchiralnonracemiconiumsaltsandcrownethersasFromtheContentseffectivephase-transfercatalystshavebeenstudiedintensively1.Introduction4223prima
3、rilyforenantioselectivecarbon–carbonorcarbon–heteroatombond-formingreactionsundermildbiphasic2.GeneralMechanismofAsymmetricconditions.AnessentialissueforoptimalasymmetriccatalysisPhase-TransferCatalysis4224istherationaldesignofcatalystsfortargetedreaction,whichallowsgenera
4、tionofawell-definedchiralionpairthatreacts3.Alkylation4225withelectrophilesinahighlyefficientandstereoselective4.MichaelAddition4251manner.Thisconcept,togetherwiththesyntheticversatilityofphase-transfercatalysis,providesareliableandgeneralstrategy5.AldolandRelatedReactions
5、4257forthepracticalasymmetricsynthesisofhighlyvaluableorganiccompounds.6.DarzensReaction42577.NeberRearrangement42588.Horner–Wadsworth–EmmonsReaction42591.Introduction9.Cyclopropanation4259In1971,Starksintroducedtheterm“phase-transfercatalysis”toexplainthecriticalroleoftet
6、raalkylammonium10.Epoxidation4259+orphosphoniumsalts(QX)inthereactionsbetweentwo[1]substanceslocatedindifferentimmisciblephases.For11.Aziridination4261example,thedisplacementreactionof1-chlorooctanewithaqueoussodiumcyanideisacceleratedmanythousandfoldby12.Oxidation4262the
7、additionofhexadecyltributylphosphoniumbromide(1)asaphase-transfercatalyst(Scheme1).Keytothistremendous13.Reduction4262enhancementinreactivityisthegenerationofaquaternaryphosphoniumcyanide,whichmakesthecyanideanionsoluble14.Fluorination4263inorganicsolventsandsufficientlynu
8、cleophilic.Thehighrateofdisplacementismainlyduetotwoofthethreecharacter-15.Sulfenylation4
