Study On Asymmetric Domino Reactions Of Nitroolefins Catalyzed By Chiral Bifuncitional Thioureas-Tertiary Amine

Domino and Michael addition reactions are (?) of most important carbon-carbon bond-forming reactions in organic synthesis. The chiral organocatalyst bearing thiourea-tertiary amine is a ideal catalyst in the asymmetric Domino and Michael addition reactions. This paper studied the asymmetric Domino reactions of nitroolefins with the organocatalysts.This dissertation included four parts. The first part reviewed the studies on asymmetric reactions catalyzed by chiral thiourea/urea organocatalysts. In the second part, we described the asymmetric Domino Michael-Aza-Henry reaction of 2-Aryl-3-Nitro-2H-chromene derivatives and azomethine ylides with Takemoto's organocatalyst. The third part was the research on the asymmetric Domino-Michael-Alkylation reaction of various 1,3-dicarbonyl compounds to a-bromonitroalkenes with quinine-derivatived bifunctional thiourea organocatalyst.In the first part of this dissertation, the recent progress on thiourea/urea, which was based on H-bonding actitivated, catalysted stereoselective reactions has been summarized.In the second part, it was investigated that the kinetic resolution of racemic 2-Aryl-3-Nitro-2H-chromene derivatives catalyzed by Takemoto's organocatalyst for the first time and chiral 2-Aryl-3-Nitro-2H-chromene derivatives were obtained. Studying on the asymmetric Domino Michael-Aza-Henry reaction of 2-Aryl-3-Nitro-2H-chromene derivatives and azomethine ylides, we found the kinetic resolution gave the optically active 2-Aryl-3-Nitro-2H-chromene derivatives with good enantioselectivities (68-87% ee), which simultaneously gave the multifunctional diethyl 3,4-diphenyl-3a-nitrobenzopyrano [3,4-c] pyrrolidine-1,1-dicarboxylate derivatives with excellent diasereoselectivities (>99/1 dr) and modera enantioselectivities (up to 70% ee) possessing four vicinal chiral carbon centers. Moreover, the absolute configurations have been confirmed.In the third part of this article, the asymmetric Domino Michael-Alkylation reaction of various 1,3-dicarbonyl compounds to a-bromonitroalkenes was described for the first time, employing readily available cinchona-derived thioureas as organocatalysts. In our research, we found, in the mild condtions, the Domino reaction, which was based on acyclic 1,3-dicarbonyl-compounds, cyclo-hexane-1,3-dione,5,5-dimethylcyclo-hexane-1,3-dione and a series of 4-hydroxythiocoumarins to a-bromonitroalkenes bearing various substitutions, afforded the chiral mono-, bi- and tricyclic 2,3-dihydrofurans with two vicinal chiral carbon centers in good yields. In addition, the designed reactions are highly regio-, chemo-, diastereo-, and enantioselective (up to 92% ee) and the absolute configurations have been confirmed.The last part was a summary of each chapter in this dissertation.