Novel Asymmetric Organocatalytic Cascade Reactions Of Nitroolefins And Aldehydes Catalyzed By Chiral Secondary Amines

Over the past decade,chemists have witnessed an explosive growth in the field of small-molecule catalysis and,particularly,the asymmetric secondary amine catalysis.In this dissertation,firstly,the mechanism of asymmetric enamine catalysis and iminium-ioncatalysis were introduced.Then,several types of domono reactions catalyzed by secondary amines were reviewed.Based on the review of the literatures,the secondary amines catalyzed Michael-Hemiaminalization domino reaction and Michael-Michael-Michael-aldol cascade reaction were studied.This dissertation includes the following three parts:(1)Some general examples of recent advances of the secondary amines catalyzed cascade reactions were summarized and reviewed.(2)A new method was developed for the enantioselective synthesis of highly functionalized 3,4-disubstituteddihydro-2(1H)-quinolinones bearing two syn contiguous stereogenic centers with excellent diastereoselectivities(up to>99:1 dr)and high to excellent enantios-electivities(up to>99%ee)via chiral secondary amine catalystis.The process combines an enantioselective organocatalytic Michael-Hemiaminalization addition and a highly efficient oxidation reaction sequence with good yields and stereoselectivity.The catalytic mechanism was studied by ESI-MS and absolute configuration of compound 6 was determined by TDDFT ECD calculations.(3)A new method was developed for the enantioselective synthesis of highly functionalized 2,3,4-trisubstituted 1,2,3,4-tetrahydroquinolines with excellent enantioselectivities(>99%)via Michael-Michael-Michael-aldol cascade reaction in mild conditions.