ASYMMETRIC EPOXIDATION OF OLEFINS BY CHIRAL DIOXIRANES

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DESCRIPTION: The overall goal of the proposed research is to develop new, efficient, catalytic asymmetric epoxidation of olefins by chiral dioxirane generated in situ from Oxone (potassium peroxymonosulfate) and chiral ketone and to apply this method to the synthesis of biologically active compounds. The new method will be developed to meet several important criteria, including simplicity, generality, flexibility, high enantioselectivity, and low toxicity. Each of these criteria is very important to the applicability of the method to the synthesis of biologically active compounds. The specific aims of the proposed research are: (1) to synthesize various chiral ketones from readily available chiral starting materials, such as carbohydrates and to test the feasibility of these chiral ketones for asymmetric epoxidation via dioxiranes; (2) to understand the mechanism and factors involved in asymmetric epoxidation of olefin by chiral dioxirane; (3) to identify the key structural elements of ketone catalyst required for high asymmetric induction and subsequently develop a ketone catalyst with high stability, reactivity, and enantioselectivity; (4) to apply the newly developed asymmetric epoxidation to the synthesis of biologically active compounds and useful chiral building blocks towards biologically active compounds.