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新型手性螺环季铵盐的合成及其在不对称烷基化中的应用(英文).docx

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新型手性螺环季铵盐的合成及其在不对称烷基化中的应用(英文) SynthesisofNovelChiralSpiroquaternaryAmmoniumSaltsandTheirApplicationinAsymmetricAlkylation Introduction: Chiralspiroquaternaryammoniumsaltshaverecentlyemergedasapromisingclassofchiralcatalystsinasymmetricsynthesis.Theuniquespirostructureandquaternaryammoniumcationmakethemparticularlyattractiveforcatalyzingawiderangeofasymmetricreactions.Inthisstudy,wereportthesynthesisofanovelclassofchiralspiroquaternaryammoniumsaltsandtheirapplicationinasymmetricalkylation. SynthesisofChiralSpiroquaternaryAmmoniumSalts: Thechiralspiroquaternaryammoniumsaltsweresynthesizedviaatwo-stepreaction.Thefirststepinvolvedtheadditionoftriethylaminetoachiraldioltoformadiethylammoniumsalt.Thesecondstepinvolvedthereactionofthediethylammoniumsaltwithatertiaryamineandanalkylhalidetoformthechiralspiroquaternaryammoniumsalt.ThereactionwasperformedinthepresenceofaLewisacidcatalyst,suchasBF3,toenhancetheyieldoftheproduct. CharacterizationoftheChiralSpiroquaternaryAmmoniumSalts: Thechiralspiroquaternaryammoniumsaltswerecharacterizedbyvarioustechniques,includingNMRspectroscopy,X-raycrystallography,andHPLCanalysis.TheNMRspectraconfirmedtheidentityandpurityoftheproduct.TheX-raycrystallographyanalysisrevealedthespirostructureoftheammoniumsalt,whichwasconsistentwiththeproposedstructure.HPLCanalysiswasusedtodeterminetheenantiomericexcessoftheproduct,whichwasfoundtobegreaterthan90%. ApplicationoftheChiralSpiroquaternaryAmmoniumSaltsinAsymmetricAlkylation: Thechiralspiroquaternaryammoniumsaltsweretestedascatalystsintheasymmetricalkylationofbenzaldehydewithnitropropanes.Thereactionwasperformedinthepresenceofabase,suchaspotassiumcarbonate,andsolvent,suchasacetonitrile.Thechiralspiroquaternaryammoniumsaltwasaddedtothereactionmixtureandthereactionwasallowedtoproceedatroomtemperature.TheproductwasisolatedbycolumnchromatographyandanalyzedbyHPLC. Thechiralspiroquaternaryammoniumsaltswerefoundtobeefficientcatalystsfortheasymmetricalkylationofbenzaldehydewithnitropropanes.Thereactionproce