The Synthesis Of Chiral Guanidines And Guanidinium Salts And Their Applocation In Asymmetric Michael Reactions

The side chain of the amino acid arginine is guanidinium, and this moiety can also present inmany natural products. The guanidinium group can generate strong ion-pairs with oxoanions such ascarboxylates or phosphates in enzymes and antibodies. As the extension of this mechanism in organicchemistry, in the past few decades, various chiral guanidines, particularly the axially chiral guanidines andthe C2-symmetric bicyclic guanidines, have been designed and synthesized, and their high pKa values anddual hydrogen-bonding modes have promoted an ever-increasing interest in asymmetric reactions.In this thesis, we have developed the first highly diastereo-and enantioselective Michaeladditions of3-benzyl-substituted oxindoles to N-maleimides catalyzed by a C2-symmetric bicyclicguanidine. Several3,3-disubstituted oxindoles with vicinal quaternary–tertiary carbon centers wereobtained. This is also the first report on the stereospecific embedment of N-benzylic α-branchedsuccinimides into the framework of3,3-disubstituted oxindoles.