噁唑硼烷催化剂及其不对称还原反应的机理研究

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1、西南师范大学硕士学位论文噁唑硼烷催化剂及其不对称还原反应的机理研究姓名：何荣幸申请学位级别：硕士专业：物理化学指导教师：李明2003.5.1StudyonOxazaborolidineCatalystsandtheMichanismofEnantioselectiveReductionReactionSpecialty：PhysicalChemistrySupervisor：ProfessorMingLiAbstractResearch：QuantumChemistryGraduate：RongxingHeTheuseofchiralmaterialsiSextensive

2、inour1ife．menantioselectivecatalyticreactionisconsideredwidelytobeai3importantwaybywhichGhiraloompoundSaregenerated．Multifariouscatalystsareusedinenantioselectivecatalyticreactionsforthesakeofobtainingchilalcompoundsandthechivaloxazabomlidinescatalystswereattachedhi吐importancetobcc’且1．1seo

3、ftheiruniquechamcteristiCS．Inthepresentpaper,theenanfioselectivereductionofprochiralketonewithboraneandtheenantioselectivereductionofproehiralaldehydewithalkynylboranecatalyzedby吐【砌oxazabomlidinesareinvestigated．respectively,bymeansofthesemi-empiriealAMlmolecularorbitalmethodandtheabinitio

4、molecularorbitalmethod．ThemechanismsoftheseenantioselecfivereductionsaI{ediscussedindetail．Computationsoftheenanfioseleetivereductionofp-me4hoxyhypnonewithboranecatab-zedbyCBScatalystsInthis哦thesemi-empiricalAMlmolecularorbitalmethodisemployedtostudytheenanfioselecfivereductionofp-methoxyh

5、ypnonewithboranecatalyzedbyGhiralpyrmlidino『3耳c1oxazaborolidine．1hecatalystandatlthestlzlcturesoftheintermediaryandthetransitionstatesinthisenanfioselectivereductionareoptimizedcompletelyandtheeffectsofvariationsinthestructuresoftheintermediaryandthetransitionslates0I"itheenantioseleetivec

6、atalyticreductionarestudied．Asshown,thecatalystandalltheintermediarystateshavenOimamaryfrequenciesandallthetransitionstateshavesoleima百naryfrequencies．11leactivatingenergiesofallthetransitionstatesareanalyzedandthereductionmechanismiSexplained．111etheoreticalresultisinagreementwiththeexper

7、iment．111econtrolling-velocitystepformeenantioselectivereductioniSthedecompositionoftheB—O-B-N4-numberedring．Q118ntllnlchemicalstudyOilthemechanismofenantioseleetivealknylationofaldehydescatalyzedoxazaborofidines丑1emechanismoftheenantioselecfivereductionofalde