Organocatalytic Asymmetric Hetero-Dielsalder Reaction Of Olefinic Azlactones

The organocatalytic asymmetric Hetero-Diels-Alder reaction is studied in this thesis. The thesis is divided into three parts:Chapter 1: Asymmetric Hetero-Diels-Alder reactions of carbonyl compounds.Since its descovery in 1928, the Diels-Alder reaction is becoming one of the most fundamental importance for the organic chemistry. Firstly, we briefly introduce some basic knowledge of DielsAlder reaction, including the definition, the classification and the reaction pathway. Owing to too much reports about Diels-Alder reactions, so we mainly review the asymmetric Hetero-Diels-Alder reactons of carbonyl compounds, including the Hetero-Diels-Alder reactions of aldehydes as well as ketone as dienophiles and the Inverse-Electron-Demand Diels-Alder reaction of carbonyl compounds. At the end of this chapter, we briefly introduce the application of Hetero-Diels-Alder reaction as key step in the total synthesis.Chapter 2: Catalytic asymmetric Hetero-Diels-Alder reaction of olefinic azlactones and isatins: facile access to chiral spirooxindole dihydropyranones.Azlactones are among the most useful starting materials for the synthesis of α-amino acids and other heterocycles. This chapter firstly introduces the application of such compounds in the organic synthesis. Spirooxindole motifs are found in a number of nature products and bioactive molecules. Many alkaloids which have pharmacological activities contain such skeleton. And then we summarized the synthesis strategy of spirooxindoles.Asymmetric Hetero-Diels-Alder reaction of olefinic azlactones and isatins was realized through organocatalytic direct γ-functionalization of azlactones. This methodology provides an efficient access to spirooxindoles, which also represents the first example of hydrogen-bondmediated asymmetric transformation of azlactone.Chapter 3: Highly enantioselective organocatalytic Hetero-Diels-Alder reactions of olefinic azlactones and α-keto esters: construction of chiral quaternary α,β-unsaturated δ-lactones.α,β-unsaturated δ-lactones is an important synthetic block in organic synthesis. Developing an efficient and simple method to synthesize this compounds is the target of organic chemists. The known synthetic methods to this molecular are mainly concentrated in Hetero-Diels-Alder reaction of carbonyl compounds, the dienes in this reactions are limited to the enolated of unsaturated compounds. The strategy that using enolated to enhance the reactivity has some disadvantage, such as poor atom economy, hard and complicated processes. To solve this problem, we developed the first organocatalytic Hetero-Diels-Alder reaction between α-keto esters with in situ generated diene. With this protocol, a wide range of desired α,β-unsaturated δ-lactones with a quaternary stereocenter were produced in generally good yields with excellent enantioselectivities.