Epoxide

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Epoxide

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Epoxide

CATEGORIES ABOUT EPOXIDE

functional groups

SHOPPER'S DELIGHT

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SYNTHESIS

Epoxides are usually created by one of the following reactions:

Olefin Peroxidation involves the oxidation of an Olefin with a Peroxide , usually a Peroxyacid like M-CPBA , and proceeds via what is commonly known as the Butterfly Mechanism ¹. It is easiest to consider the oxygen to be an Electrophile , and the alkene a Nucleophile , although they both operate in that capacity, and the reaction is considered to be concerted (the numbers in the mechanism below are for simplification).

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Enantioselective alkene epoxidations can be found in the Sharpless Epoxidation , the Jacobsen Epoxidation and the Shi Epoxidation .

Intramolecular SN2 substitution. This method is a variant of the Williamson Ether Synthesis . In this case, the Alkoxide Ion and the Halide are right next to each other in the same molecule (such compounds are generically called Halohydrins ), which makes this a simple ring closure reaction.

In the Johnson-Corey-Chaykovsky Reaction epoxides are generated from Carbonyl groups and Sulfonium Ylide s.

REACTIONS

Nucleophilic Addition to an epoxide can be base or acid catalyzed.

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Hydrolysis of an epoxide in presence of an Acid Catalyst generates a Glycol . The Hydrolysis process of epoxides can be considered to be the Nucleophilic Addition of water to the epoxide under Acidic conditions.

Reduction of an epoxide with Lithium Aluminium Hydride and Water generates an Alcohol . This reduction process can be considered to be the nucleophilic addition of hydride (H-) to the epoxide under basic conditions.

SEE ALSO

Polyether s

REFERENCES

¹ Bartlett ''Rec. Chem. Prog'' 1950, ''11'' 47.