Amide Catalyzed Enantioselective Synthesis Of Substituted Pyrans And Synthesis Of Spiro-Cyclopropane

Chiral tertiary amine catalyzed formal [4+2] Cycloaddition of allene ketones and electron-deficient olefin has various advantages such as high efficiency, operational simplicity and environmentally friendliness, especially in the synthesis of polysubstituted chiral pyran derivatives via simple substrates. Chiral tertiary amine catalyst could be achieved from natural amino acid and cinchona alkaloid through some simple operations, which is cheap, stable in the air and has diversity of chirality. This thesis mainly focus on the following three chapters:Chapter 1:This chapter introduced the research history and recent advances in the field of nucleophilic organocatalysis, which mainly include nucleophilic phosphine organocatalysis and amine catalysis of allenoates.Chapter 2:This chapter firstly described the recent advances of allenoates in the synthesis of pyran derivatives catalyzed by tertiary amine and the applications of allene ketones in the nucleophilic organocatalysis. Then we presented a cinchona alkaloid amide catalyzed enantioselective synthesis of 4H-pyran derivatives from allene ketones and β,γ-unsaturated a-carbonyl butyrolactam. The results showed that quinidine derived catalyst could give excellent yield and enantioselectivity.Chapter 3:This chapter presented the general synthesis of cyclopropane and the recent progresses of sulfur ylide in the organic synthesis. Next we described an efficient base-promoted spiro-cyclopropanation of 2,3-dioxopyrrolidine derivatives with sulfonium salts in a mild condition. This reaction enables a novel concise access to polysubstituted spiro-cyclopropane derivatives in good yields with up to> 20:1 trans/cis ratio.