Exploiting Hydroxamic Acids as Organocatalysts for the Epoxidation of Alkenes with Hydrogen Peroxide as the Oxidant

An organocatalytic epoxidation of alkenes synthesis is presented in which hydroxamic acids are used as the catalyst and hydrogen peroxide as the green oxidant. Mechanistic studies by direct infusion HRMS provide experimental evidence for the formation of various intermediates.

Abstract

The epoxidation of alkenes has altered and reshaped the way scientists think in modern organic synthesis. Herein, a novel, sustainable and eco-friendly protocol for the epoxidation of alkenes is reported, utilizing hydrogen peroxide as the green oxidant and, for the first time, hydroxamic acid derivatives as the organocatalyst. The presented methodology is very effective, leading to good to high yields for the oxidation of a variety of olefins, while various functional groups are well tolerated. Mechanistic studies utilizing direct infusion high resolution mass spectrometry (DI-HRMS) provide strong evidence for the mechanism of the organocatalytic oxidation.

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