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Title: Carbon-hydrogen vs. carbon-carbon bond cleavage of 1,2-diarylethane radical cations in acetonitrile-water

Journal Article · · J. Org. Chem.; (United States)
DOI:https://doi.org/10.1021/jo00183a023· OSTI ID:6636945

Radical cations of 1,2-diarylethanes and 1-phenyl-2-arylethanes (Ar = phenyl, p-tolyl, p-anisyl) were generated in acidic 70% acetonitrile-water by Cu/sup 2 +/-catalyzed peroxydisulfate oxidation. The radical cations fragment mainly by loss of benzylic protons (C-H cleavage) rather than by alkyl C-C bond cleavage. The 1,2-diarylethanol products undergo further selective oxidation to aryl aldehydes and arylmethanols via rapid equilibration of diarylethane and diarylethanol radical cations. The radical cation of 2,3-dimethyl-2,3-diphenylbutane fragments efficiently by C-C cleavage, forming cumyl radical and cumyl cation. Oxidations of bibenzyl-bicumyl mixtures show selective oxidation of bicumyl dependent on total substrate concentration, providing evidence of equilibrating radical cations and showing that bicumyl fragments faster than bibenzyl loses protons. The effects of reaction conditions and substrate structure on reactivity are discussed.

Research Organization:
Battelle Pacific Northwest Labs., Richland, WA
OSTI ID:
6636945
Journal Information:
J. Org. Chem.; (United States), Vol. 49:9
Country of Publication:
United States
Language:
English