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Preparation of Epoxides

Preparation of Epoxides

Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
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Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of...

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Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
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Related Experiment Video

Updated: Jul 29, 2025

From a Natural Product to Its Biosynthetic Gene Cluster: A Demonstration Using Polyketomycin from Streptomyces diastatochromogenes Tü6028

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Modular Oxime Formation by a trans-AT Polyketide Synthase.

Hannah A Minas¹, Romain M M François^1,2, Franziska Hemmerling¹

¹Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zürich, Vladimir-Prelog-Weg 4, 8093, Zürich, Switzerland.

Angewandte Chemie (International Ed. in English)

|May 22, 2023

Summary

Modular trans-acyltransferase polyketide synthases (trans-AT PKSs) create diverse natural products. This study reveals an unusual oxygenase module that installs methylated oximes on-line, expanding the toolbox for trans-AT PKS engineering.

Keywords:

Bacterial Natural Products Biosynthesis Oxime Polyketides X-Ray Crystallography

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Published on: February 6, 2020

Area of Science:

Biochemistry
Molecular Biology
Natural Product Biosynthesis

Background:

Modular trans-acyltransferase polyketide synthases (trans-AT PKSs) are crucial for synthesizing complex polyketide natural products.
trans-AT PKSs offer greater chemical diversity compared to cis-AT PKSs.
The lobatamide A PKS is a notable example, featuring a unique methylated oxime modification.

Purpose of the Study:

To biochemically characterize the mechanism of oxime formation in the lobatamide A PKS.
To elucidate the structural basis of the oxygenase's catalytic activity and protein interactions.
To expand the engineering capabilities of trans-AT PKS for novel polyketide synthesis.

Main Methods:

Biochemical assays to demonstrate on-line functionality of the oxygenase module.
X-ray crystallography to determine the oxygenase crystal structure.
Site-directed mutagenesis to identify key residues and interactions.

Main Results:

The unusual oxygenase-containing bimodule was confirmed to install methylated oximes on-line.
A catalytic model for the oxygenase was proposed based on structural analysis and mutagenesis.
Key protein-protein interactions essential for the observed chemistry were identified.

Conclusions:

Oxime-forming machinery has been added to the biomolecular engineering toolbox for trans-AT PKS.
This advancement enables the introduction of masked aldehyde functionalities into diverse polyketides.
The findings pave the way for creating novel polyketide natural products with tailored chemical properties.