Aryloxenium ions

Dimroth, K. Arylated Phenols, Aroxyl Radicals and Aryloxenium Ions Syntheses and Properties. /29, 99-172 (1985). 

Alkyl- and aryloxenium ions (RO+) are similarly too reactive to be observed however, they may be involved in the oxidation of alkanes under superacidic... 

Oxidations of variously-substituted 4-alkyl- and 4-alkoxyphenols with BAIB or BTIB in alcoholic solvents provide ready access to alkoxy(alkyl)- and dialkoxycyclohexadienones (Scheme 23) [70-72]. Dienone formation is generally attributed to the capture of aryloxyiodane and/or aryloxenium ion intermediates with the alcohol [73]. Related C-0 bond forming oxidations of phenols with BAIB and BTIB, including intramolecular cyclizations leading to spiro-dienones, are summarized in several reviews [1 - 3,74]. 

DAIB and BTIB oxidations of phenols proceed through aryloxyiodane 129 and/or aryloxenium ion 130 intermediates and are quite useful for the preparation of quinones, quinol ethers, and quinone acetals (e.g., Scheme 39) (88TL677, 92MI2, 93JCS(P1)1891, 01OR327). When phenols bearing nucleophilic side chains are used as substrates, such oxidations provide fertile ground for the assembly of heterocyclic structures. This can be accomplished by oxidative-cyclization reactions of different types. 

Arylated Phenols, Aroxyl Radicals and Aryloxenium Ions... 

Arylated Phenols, AroxyJ Radicals and Aryloxenium Ions Syntheses and Properties... 

When N-tosylated phenylhydroxylamines are treated with trifluoroacetic acid in the presence of benzene, 2- and 4-hydroxybiphenyl are found in yields of 25% and 20%, respectively. The aryloxenium ion is believed to be the intermediate56). No higher arylated phenol derivatives have been examined. 

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