18099-96-2Relevant academic research and scientific papers
Dearomatization of Electron-Deficient Phenols to ortho-Quinones: Bidentate Nitrogen-Ligated Iodine(V) Reagents
Xiao, Xiao,Greenwood, Nathaniel S.,Wengryniuk, Sarah E.
supporting information, p. 16181 - 16187 (2019/11/05)
Despite their broad utility, the synthesis of ortho-quinones remains a significant challenge, in particular, access to electron-deficient derivatives remains an unsolved problem. Reported here is the first general method for the synthesis of electron-deficient ortho-quinones by direct oxidation of phenols. The reaction is enabled by a novel bidentate nitrogen-ligated iodine(V) reagent, a previously unexplored class of compounds which we have termed Bi(N)-HVIs. The reaction is extremely general and proceeds with excellent regioselectivity for the ortho over para isomer. Functionalization of the ortho-quinone products was examined, resulting in a facile one-pot synthesis of catechols, as well as the incorporation of a variety of heteroatom nucleophiles. This method represents the first synthetic application of Bi(N)-HVIs and demonstrates their potential as a platform for the further development of highly reactive, but also highly tunable, I(V) reagents.
Rearrangements in the Cerium(IV) and Manganese(III) Oxidations of Substituted Naphthalenes and the NIH Shift Mechanism
Bhatt, M. Vivekananda,Periasamy, Mariappan
, p. 3575 - 3586 (2007/10/02)
Ceric ammonium sulphate oxidation of 1- and 1,4-disubstituted naphthalenes gives 2- and/or 2,3-disubstituted 1,4-naphthoquinones through migration of substituents (D, Br, Ph).Similar rearrangements are also observed in the manganese(III) oxidation and also in the anodic oxidation of these substrates.The results are consistent with the proposal that these oxidations go through the formation of radical cation followed by reaction with H2O and further oxidation of the radical to the carbocationic intermediate on the way to the corresponding 1,4-naphthoquinone.Oxidation of 1,4-diphenylnaphthalene gives 2,3-diphenyl-1,4-naphthoquinone or 4-hydroxy-2,4-diphenyl-1(4)H-naphthalenone.The results are in accordance with the conclusion that such rearrangements do not require prior formation of arene oxide intermediates, originally proposed for the NIH shift mechanism.
