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氮杂醇手性配体在锌催化的不对称Henry反应中的应用(英文).docx

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氮杂醇手性配体在锌催化的不对称Henry反应中的应用(英文) Chiralnitrogen-containingalcoholshaveemergedasimportantligandsinasymmetriccatalysisduetotheirabilitytocoordinatetotransitionmetalsandcontrolthestereochemistryofchemicalreactions.Inrecentyears,therehasbeengrowinginterestintheirapplicationasligandsinthezinc-catalyzedasymmetricHenryreaction. TheHenryreactioninvolvestheadditionofanucleophiletoanaldehydeoraketonetoformanewcarbon-carbonbond.Itisanimportantreactioninorganicsynthesis,asitallowstheconstructionofchiralβ-hydroxyketonesandalcohols,whichareversatilebuildingblocksforthesynthesisofpharmaceuticals,naturalproducts,andotherorganicmolecules. OneofthechallengesintheHenryreactioniscontrollingthestereochemistryoftheproduct.Traditionalapproachesinvolveusingchiralauxiliariesorchiralcatalyststoinduceasymmetry.However,chiralnitrogen-containingalcoholshaveemergedasapromisingalternativeduetotheirabilitytochelatetometalcatalystsandcontrolthestereochemistryofthereaction. Zinc-catalyzedasymmetricHenryreactionsusingchiralnitrogen-containingalcoholsasligandshavebeenreportedinanumberofstudies.Forexample,Liuandco-workersreportedthesynthesisofβ-hydroxyketoneswithhighenantioselectivityusingachiralnitrogen-containingalcoholligandinthepresenceofazinccatalyst.Theauthorsfoundthatthereactionproceededefficientlyundermildconditions,andtheresultingproductswereobtainedinhighyieldandwithgoodstereocontrol. Similarly,Shiandco-workersreportedthesynthesisofchiralβ-hydroxyindanoneswithhighenantioselectivityusingachiralnitrogen-containingalcoholligandinthepresenceofazinccatalyst.Theauthorsfoundthatthepresenceofthechiralligandwasessentialforcontrollingthestereochemistryofthereactionandachievinghighenantioselectivity. Themechanismofthezinc-catalyzedasymmetricHenryreactionusingchiralnitrogen-containingalcoholsasligandsisstillnotcompletelyunderstood.However,itisbelievedthatthechiralligandcoordinatestothezinccatalyst,formingacomplexthatcontrolsthestereochemistryofthereaction.Thechiralligandmayalsostabilizethetransitionstate,l