SYNTHESIS OF A-HYDROXYCARBONYL COMPOUNDS

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The aim of the proposed work is to develop methodology for the direct oxidation and asymmetric oxidation of enolates to Alpha-hydroxycarbonyl compounds (R2C(OH)C(O)-Z). Compounds having the Alpha-hydroxycarbonyl structural unit are ubiquitous in nature and responsible, for the biological activity of many compounds having this subunit. These goals will be achieved by exploring the oxidation of enolates (enol silyl ethers, enamines, metaloenamines) using 2-sulfonyloxaziridines, aprotic and neutral oxidizing agents. Oxidation of chiral enolates using these reagents is anticipated to give optically active Alpha-hydroxycarbonyl compounds in high optical purity. Studies of enolate oxidations with chiral 2-sulfonyl- and 2-sulfamyloxaziridines will provide insights into the origins of asymmetric induction and new information on electrophile-enolate trajectories. Metal assisted asymmetric oxidations using 2-sulfamyloxaziridines having metal chelating functional groups are anticipated to give Alpha-hydroxycarbonyl compounds in high enantiotopic purity. This methodology will be applied to the chiral synthesis of (-)-Eucomol and (+)-demethoxydaunomycinone; the latter compound is a potent anti-tumor agent. The feasibility of direct enolate and asymmetric enolate oxidation as a viable synthetic route to Alpha-hydroxycarbonyl compounds has been demonstrated by preliminary studies.