According to (1) addition of O2 in acid to lithiated benzene makes phenol.

I'm trying to deduce the mechanism, and somehow it doesn't feel right but I'm not sure.

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(1) Snieckus, V. Directed ortho metalation. Tertiary amide and O-carbamate directors in synthetic strategies for polysubstituted aromatics. Chem. Rev. 1990, 90 (6), 879–933. DOI: 10.1021/cr00104a001.

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    $\begingroup$ Addition of oxygen followed by acid work up, not oxygen in acid $\endgroup$ – Waylander Dec 27 '19 at 19:44
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    $\begingroup$ Your proposed mechanism doesn't quite work; loss of H2O would lead to a six-electron oxygen species (that should already set off alarm bells), and to get back its octet, that oxygen would have to pick up the equivalent of a hydride, not a proton (from water). Based on the original paper pubs.acs.org/doi/abs/10.1021/jo00380a034 that Snieckus cites there isn't any attempt to generate singlet O2, so I imagine that the mechanism is (at least partly) radical, but I don't have a concrete suggestion in mind. $\endgroup$ – orthocresol Dec 28 '19 at 1:04
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    $\begingroup$ In addition, @Waylander's comment is a very salient point which you should pay more attention to, imo: it is oxygen followed by acid, not at the same time (that would be rather pointless, as adding any kind of acidic solution - $\ce{O2}$ or not - to an organolithium would simply protonate it). So we presumably need to react $\ce{ArLi}$ with $\ce{O2}$ (with a radical mechanism) to get to a phenoxide $\ce{ArO-}$, which upon workup forms the phenol $\ce{ArOH}$. Not trivial... $\endgroup$ – orthocresol Dec 28 '19 at 1:07
  • $\begingroup$ @orthocresol: There is the possibility that the aryl hydroperoxide generated during workup oxidizes TMEDA. but I am not convinced. $\endgroup$ – user55119 Dec 28 '19 at 2:33

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