Author

Mingming Han

Date of Award

9-3-1999

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

First Advisor

Irina P. Smoliakova

Abstract

This Ph.D. dissertation is focused on the stereoselective synthesis of β- C-glycosides. Such carbohydrate derivatives have been found to possess a wide spectrum of physiological activities. They can serve as non-hydrolizable enzyme inhibitors. C-Glycosides have been used as chiral precursors for synthesis of other compounds. The synthesis of β-C-glycosides is based on the fact that, in the presence of Lewis acids, ArSCl adducts of glycals can be converted to active intermediates, episulfonium ions. These intermediates are known to react with a number of C-nucleophiles. In this study, the reaction of ArSCl adducts of glycals with vinyl ethers was investigated. To determine the scope and limitation of the reaction, different unsaturated carbohydrate derivatives and vinyl ethers were used. The reaction mechanism and the factors influencing regio- and stereo selectivity of C-C bond formation were studied. The synthesized compounds by this method have an ArS group attached to position 2 of the carbohydrate ring. Removal of this group leads to the preparation of 2-deoxy-β-C-glycosides, which are valuable substrates in synthetic carbohydrate chemistry.

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