CCl3CN: a crucial promoter of mCPBA-mediated direct ether oxidation.

The direct oxidation of ether sp(3) C-H bonds using the new reagent system mCPBA/CCl(3)CN/MeCN has been developed. CCl(3)CN in MeCN drastically alters the reactivity of m-chloroperbenzoic acid (mCPBA), and chemoselective transformation of methyl ethers to ketones was realized under mild conditions. Radical-based mCPBA-mediated oxidation was suggested as the reaction mechanism. The present new reaction expands the utility of methyl ethers as stable synthetic precursors of carbonyl compounds and of mCPBA as a radical-based C-H oxidizing agent.