106910-48-9Relevant articles and documents
Copper-catalyzed homolytic and heterolytic benzylic and allylic oxidation using tert-butyl hydroperoxide
Rothenberg, Gadi,Feldberg, Liron,Wiener, Harold,Sasson, Yoel
, p. 2429 - 2434 (1998)
Allylic and benzylic alcohols were oxidized in good yields to the respective ketones by tert-butyl hydroperoxide (TBHP) in the presence of copper salts under phase-transfer catalysis conditions. This dehydrogenation was found to proceed via a heterolytic mechanism. CuCl2, CuCl, and even copper powder were equally facile as catalysts, as they were all transformed in situ to Cu(OH)Cl which was extracted into the organic phase by the phase-transfer catalyst (PTC). Deuterium labeling experiments evidenced the scission of the benzylic C-H bond in the rate-determining step. Nonproductive TBHP decomposition was not observed in the presence of the alcohol substrates. Conversely, the oxygenation of π-activated methylene groups in the same medium was found to be a free radical process, and the major products were the appropriate tert-butyl peroxides. Catalyst deactivation, solvent effects, and extraction effects are discussed. By applying Minisci's postulations concerning the relative reactivity of TBHP molecules towards tert-butoxyl radicals in protic and nonprotic environments, the coexistence of the homolytic and the heterolytic pathways can be explained. A complete reaction mechanism is proposed, wherein the free-radical oxidation obeys Kochi's mechanism, and the heterolytic dehydrogenation is based on either a high-valent CuIV=O species or a [Cu(OH)Cl]2 species.
THE SELECTIVE FUNCTIONALIZATION OF SATURATED HYDROCARBONS. PART 28. THE ACTIVATION OF BENZYLIC METHYLENE GROUPS UNDER GOAGGIV AND GOAGGV CONDITIONS
Barton, Derek H. R.,Wang, Tie-Lin
, p. 1011 - 1032 (1994)
Under GoAggIV and GoAggV conditions, cyclohexadienes were oxidized to give aromatic products instead of ketones and alcohols.At the same time, anthracene was oxidized to give anthraquinone.Under GoAggIV and GoAggV conditions, xanthene, fluorene and diphenylmethane were oxidized to give the corresponding xanthone, fluorenone and benzophenone following two possible pathways: a) alkane to alkyl t-butylperoxide to ketone, and b) alkane to ketone, in which alkyl hydroperoxide, derived from oxygen, may be the reaction intermediate.Xanthyl azide was formed when sodium azide was added to the reaction mixture of xanthene under GoAggIV and GoAggV conditions.The reaction of triphenylmethane under GoAggV conditions gave triphenylmethyl t-butyl peroxide as the major product and hydroperoxide as the minor product.When TEMPO was added, triphenylmethyl hydroperoxide was the only product.
Green Organic Solvent-Free Oxidation of Alkylarenes with tert-Butyl Hydroperoxide Catalyzed by Water-Soluble Copper Complex
Ajjou, Abdelaziz Nait,Rahman, Ateeq
, p. 165 - 174 (2020/04/15)
Different benzylic compounds were efficiently oxidized to the corresponding ketones with aqueous 70% tert-butyl hydroperoxide (TBHP) and the catalytic system composed of CuCl2.2H2O and 2,2'-biquinoline-4,4'-dicarboxylic acid dipotassium salt (BQC). The catalytic system CuCl2/BQC/TBHP allows obtaining high yields at room temperature under organic solvent-free conditions. The interest of this system lies in its cost effectiveness and its benign nature towards the environment. Benzylic tertbutylperoxy ethers and benzylic alcohols were observed and suggested as the reaction intermediates. Analysis of organic products by atomic absorption did not show any contamination with copper metal. In terms of efficiency, CuCl2/BQC system is comparable or superior to the most of the catalytic systems described in the literature and which are based on toxic organic solvent.
