Title

Catalytic Asymmetric Epoxidation Using a Fructose-Derived Catalyst

ACS Citation

Burke, A.; Dillon, P.; Martin, K.; Hanks, T. W. Catalytic Asymmetric Epoxidation Using a Fructose-Derived Catalyst. J. Chem. Educ. 2000, 77, 271-271.

Abstract

Modern epoxidation methods are able to create two adjacent stereocenters with very high enantioselectivity. Opening of the epoxides with nucleophiles permits rapid entry into complex organic systems, making this powerful synthetic methodology one of the fundamental reactions in organic synthesis. Various reagents for generating epoxides have been developed, including the dioxiranes. These oxidants are typically generated in situ from a ketone. Recently, a chiral dioxirane has been prepared from fructose and shown to catalytically deliver an oxygen from a simple, symmetrical oxidant to a wide variety of alkenes in very high yields and with excellent selectivity. This reaction makes an effective experiment for advanced undergraduates. Both the synthesis of the catalyst and the epoxide product are easily purified and lend themselves well to analysis by the standard array of techniques available to the organic chemist. Enantioselectivity can be determined either by polarimetry or by NMR shift experiments. In addition, the mechanism of the asymmetric epoxidation can be explored by a combination of computer modeling and student-proposed research experiments. Modern epoxidation methods are able to create two adjacent stereocenters with very high enantioselectivity. Opening of the epoxides with nucleophiles permits rapid entry into complex organic systems, making this powerful synthetic methodology one of the fundamental reactions in organic synthesis. Various reagents for generating epoxides have been developed, including the dioxiranes. These oxidants are typically generated in situ from a ketone. Recently, a chiral dioxirane has been prepared from fructose and shown to catalytically deliver an oxygen from a simple, symmetrical oxidant to a wide variety of alkenes in very high yields and with excellent selectivity. This reaction makes an effective experiment for advanced undergraduates. Both the synthesis of the catalyst and the epoxide product are easily purified and lend themselves well to analysis by the standard array of techniques available to the organic chemist. Enantioselectivity can be determined either by polarimetry or by NMR shift experiments. In addition, the mechanism of the asymmetric epoxidation can be explored by a combination of computer modeling and student-proposed research experiments.

Source Name

Journal of Chemical Education

Publication Date

1-1-2000

Volume

77

Issue

2

Page(s)

6415-6415

Document Type

Citation

Citation Type

Article