Unexpected, Latent Radical Reaction of Methane Propagated by Trifluoromethyl Radicals

Unexpected, Latent Radical Reaction of Methane Propagated by Trifluoromethyl Radicals
Nima Zargari,† Pierre Winter,‡ Yong Liang,§ Joo Ho Lee,† Andrew Cooksy,*,‡ K. N. Houk,*,§ and Kyung Woon Jung*,†
†Loker Hydrocarbon Research Institute, Department of Chemistry, University of Southern California, 837 Bloom Walk, Los Angeles, California 90089, United States
‡Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego California 92182, United States
§Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States

J. Org. Chem. 2016, 81, 9820-9825.
http://pubs.acs.org/doi/pdf/10.1021/acs.joc.6b01903

Abstract:
 

Thorough mechanistic studies and DFT calculations revealed a background radical pathway latent in metal-catalyzed oxidation reactions of methane at low temperatures. Use of hydrogen peroxide with TFAA generated a trifluoromethyl radical (•CF3), which in turn reacted with methane gas to selectively yield acetic acid. It was found that the methyl carbon of the product was derived from methane, while the carbonyl carbon was derived from TFAA. Computational studies also support these findings, revealing the reaction cycle to be energetically favorable. 

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