The Research About The Synthesis Of Phenylsulfonyl α, β-unsaturated Ketones And Their Applications In Asymmetric Diels-Alder Reaction Catalyzed By Lewis Acid And Chiral Titanium Reagents. The Mechanism Was Approached

Asymmetric synthesis is one of the most important parts in organic synthesis. It is a type of selective reaction by using chiral catalysts, chiral reagents, chiral solvents and other chiral factors. Asymmetric synthesis is applicated in the research of complicated moleculars, medicine, pesticide and food additive. It is one of the major means to get along well with the environment.The dissertation is consisted three parts. The first part reviewed the dienophiles and synthesized phenylsulfonyl , -unsaturated ketones. The second part was about the Diels-Alder reaction of phenylsulfonyl , -unsaturated ketones and cyclopentadiene. In the third part, the research on the mechanism was carried out.In the first part, two methods were used in the synthesis of phenylsulfonyl , -unsaturated ketones. As to the first method, Benzenesulfinic acid sodium salt, chloracetone reacted in ethanol, the product phenylsulfonyl actone was dissolved in THF, at 0掳C, after LDA generated, it reacted with phenylsulfonyl actone, the mixture was cooled to -78 , then added substituted adehydes gave 4-hydroxyl-1-phenylsul-fonyl-2-ones, by dehydration, phenylsulfonyl , -unsaturated ketones produced. Meanwhile, we found a new way, it was the first time we used brominated reagent to synthesize phenylsulfonyl , -unsaturated ketones, which overcame the shortcoming in very low temperature of the old one, 4-phenyl-l-phenylsulfonyl-3-butene-2-one and 4-(4-nitrophen-yl)-l-phenylsulfonyl-3-butene-2-one were produced.In the process of Diels-Alder reaction, we studied the Diels-Alder reaction of 4-phenyl-l-phenylsulfonyl-3-butene-2-one and cyclopentadiene catalyzed by zinc iodide in room temperature and got raceme in good yield. At the same time, we used chiral Titanium catalyst from chiral1, 4-diol and -dichlorodiisopropoxytitanium in the presence of Molecular Sieves 4A and got 100%ee (5S, 6R)-6-phenyl-5-(phenylsulfonylacetyl)-bicyclo[2. 2. l]-hept-2-ene, the product formed crystal, X-Ray drawing was made. What is more, ( ) -BINOL was synthesized, we used N-benzylcin-choninium chloride as host and had ( ) -BINOL separated.According to the result of asymmetric Diels-Alder reaction of phenyl-sulfonyl a , P-unsaturated ketones and cyclopentadiene catalyzed by chiral Titanium catalysts and the structure of crystal, we discussed the mechanism of asymmetric Diels-Alder reaction.