3481-02-5Relevant articles and documents
Oxygen acidity of ring methoxylated 1,1-diarylalkanol radical cations bearing α-cyclopropyl groups. The competition between O-neophyl shift and C-cyclopropyl β-scission in the intermediate 1,1-diarylalkoxyl radicals
Bietti, Massimo,Fiorentini, Simone,Pato, Iria Perez,Salamone, Michela
, p. 3167 - 3175 (2006)
A product and time-resolved kinetic study on the reactivity of the radical cations generated from cyclopropyl(4-methoxyphenyl)phenylmethanol (1) and cyclopropyl[bis(4-methoxyphenyl)]methanol (2) has been carried out in aqueous solution. In acidic solution, 1.+ and 2.+ display very low reactivities toward fragmentation, consistent with the presence of groups at Cα (aryl and cyclopropyl) that after Cα-C β bond cleavage would produce relatively unstable carbon-centered radicals. In basic solution, 1.+ and 2.+ display oxygen acidity, undergoing -OH-induced deprotonation from the α-OH group, leading to the corresponding 1,1-diarylalkoxyl radicals 1r. and 2r., respectively, as directly observed by time-resolved spectroscopy. The product distributions observed in the reactions of 1.+ and 2.+ under these conditions (cyclopropyl phenyl ketone, cyclopropyl(4-methoxyphenyl) ketone, and 4-methoxybenzophenone from 1.+; cyclopropyl(4-methoxyphenyl) ketone and 4,4′- dimethoxybenzophenone from 2.+) have been rationalized in terms of a water-induced competition between O-neophyl shift and C-cyclopropyl β-scission in the intermediate 1,1-diarylalkoxyl radicals 1r. and 2r..
Efficient and eco-compatible transition metal-free Oppenauer-type oxidation of alcohols
Ballester, Jorge,Caminade, Anne-Marie,Majoral, Jean-Pierre,Taillefer, Marc,Ouali, Armelle
, p. 58 - 62 (2014)
Catalytic amounts of cheap, non-toxic, easy-to-handle and non-sensitive sodium tert-butoxide are able to promote the dehydrogenative oxidation of a wide array of secondary alcohols using inexpensive benzophenone as the H-acceptor. The corresponding ketones, highly important intermediates and targets throughout life and material sciences, are very selectively obtained under mild conditions.
Aquacatalytic aerobic oxidation of benzylic alcohols with a self-supported bipyridyl-palladium complex
Osako, Takao,Uozumi, Yasuhiro
, p. 902 - 903 (2009)
The aerobic oxidation of alcohols was promoted in water under atmospheric molecular oxygen by a readily recyclable self-supported bipyridyl-palladium polymeric complex, which was prepared via construction of a metal-organic framework (MOF) of a bipyridyl-palladium complex bearing carboxylic groups and a copper(II) linker. Copyright
Zwitterion-induced organic-metal hybrid catalysis in aerobic oxidation
Hu, Rong-Bin,Lam, Ying-Pong,Ng, Wing-Hin,Wong, Chun-Yuen,Yeung, Ying-Yeung
, p. 3498 - 3506 (2021/04/07)
In many metal catalyses, the traditional strategy of removing chloride ions is to add silver salts via anion exchange to obtain highly active catalysts. Herein, we reported an alternative strategy of removing chloride anions from ruthenium trichloride using an organic [P+-N-] zwitterionic compound via multiple hydrogen bond interactions. The resultant organic-metal hybrid catalytic system has successfully been applied to the aerobic oxidation of alcohols, tetrahydroquinolines, and indolines under mild conditions. The performance of zwitterion is far superior to that of many other common Lewis bases or Br?nsted bases. Mechanistic studies revealed that the zwitterion triggers the dissociation of chloride from ruthenium trichloride via nonclassical hydrogen bond interaction. Preliminary studies show that the zwitterion is applicable to catalytic transfer semi-hydrogenation.
V2O5@TiO2 Catalyzed Green and Selective Oxidation of Alcohols, Alkylbenzenes and Styrenes to Carbonyls
Upadhyay, Rahul,Kumar, Shashi,Maurya, Sushil K.
, p. 3594 - 3600 (2021/07/02)
The versatile application of different functional groups such as alcohols (1° and 2°), alkyl arenes, and (aryl)olefins to construct carbon-oxygen bond via oxidation is an area of intense research. Here, we report a reusable heterogeneous V2O5@TiO2 catalyzed selective oxidation of various functionalities utilizing different mild and eco-compatible oxidants under greener reaction conditions. The method was successfully applied for the alcohol oxidation, oxidative scission of styrenes, and benzylic C?H oxidation to their corresponding aldehydes and ketones. The utilization of mild and eco-friendly oxidizing reagents such as K2S2O8, H2O2 (30 % aq.), TBHP (70 % aq.), broad substrate scope, gram-scale synthesis, and catalyst recyclability are notable features of the developed protocol.
Visible light mediated selective oxidation of alcohols and oxidative dehydrogenation of N-heterocycles using scalable and reusable La-doped NiWO4nanoparticles
Abinaya, R.,Balasubramaniam, K. K.,Baskar, B.,Divya, P.,Mani Rahulan, K.,Rahman, Abdul,Sridhar, R.,Srinath, S.
, p. 5990 - 6007 (2021/08/24)
Visible light-mediated selective and efficient oxidation of various primary/secondary benzyl alcohols to aldehydes/ketones and oxidative dehydrogenation (ODH) of partially saturated heterocycles using a scalable and reusable heterogeneous photoredox catalyst in aqueous medium are described. A systematic study led to a selective synthesis of aldehydes under an argon atmosphere while the ODH of partially saturated heterocycles under an oxygen atmosphere resulted in very good to excellent yields. The methodology is atom economical and exhibits excellent tolerance towards various functional groups, and broad substrate scope. Furthermore, a one-pot procedure was developed for the sequential oxidation of benzyl alcohols and heteroaryl carbinols followed by the Pictet-Spengler cyclization and then aromatization to obtain the β-carbolines in high isolated yields. This methodology was found to be suitable for scale up and reusability. To the best of our knowledge, this is the first report on the oxidation of structurally diverse aryl carbinols and ODH of partially saturated N-heterocycles using a recyclable and heterogeneous photoredox catalyst under environmentally friendly conditions.
Poly(ethylene glycol) dimethyl ether mediated oxidative scission of aromatic olefins to carbonyl compounds by molecular oxygen
Yu, Tao,Guo, Mingqing,Wen, Simiaomiao,Zhao, Rongrong,Wang, Jinlong,Sun, Yanli,Liu, Qixing,Zhou, Haifeng
, p. 13848 - 13852 (2021/04/22)
A simple, and practical oxidative scission of aromatic olefins to carbonyl compounds using O2as the sole oxidant with poly(ethylene glycol) dimethyl ether as a benign solvent has been developed. A wide range of monosubstituted,gem-disubstituted, 1,2-disubstituted, trisubstituted and tetrasubstituted aromatic olefins was successfully converted into the corresponding aldehydes and ketones in excellent yields even with gram-scale reaction. Some control experiments were also conducted to support a possible reaction pathway.
Method for preparing aldehyde ketone compound through olefin oxidation
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Paragraph 0019, (2021/04/07)
The invention provides a method for preparing an aldehyde ketone compound by olefin oxidation, which relates to an olefin oxidative cracking reaction in which oxygen participates. The method comprises the following specific steps: in the presence of a solvent and an oxidant, carrying out oxidative cracking on an olefin raw material to obtain a corresponding aldehyde ketone product. Compared with the traditional method, the method does not need to add any catalyst or ligand, does not need to use high-pressure oxygen, has the advantages of simple and mild reaction conditions, environment friendliness, low cost, high atom economy and the like, is wide in substrate application range and high in yield, and has a wide application prospect in the aspects of synthesis of aldehyde ketone medical intermediates and chemical raw materials.
Oxidative Cleavage of Alkenes by O2with a Non-Heme Manganese Catalyst
Bennett, Elliot L.,Brookfield, Adam,Guan, Renpeng,Huang, Zhiliang,Mcinnes, Eric J. L.,Robertson, Craig M.,Shanmugam, Muralidharan,Xiao, Jianliang
supporting information, p. 10005 - 10013 (2021/07/19)
The oxidative cleavage of C═C double bonds with molecular oxygen to produce carbonyl compounds is an important transformation in chemical and pharmaceutical synthesis. In nature, enzymes containing the first-row transition metals, particularly heme and non-heme iron-dependent enzymes, readily activate O2 and oxidatively cleave C═C bonds with exquisite precision under ambient conditions. The reaction remains challenging for synthetic chemists, however. There are only a small number of known synthetic metal catalysts that allow for the oxidative cleavage of alkenes at an atmospheric pressure of O2, with very few known to catalyze the cleavage of nonactivated alkenes. In this work, we describe a light-driven, Mn-catalyzed protocol for the selective oxidation of alkenes to carbonyls under 1 atm of O2. For the first time, aromatic as well as various nonactivated aliphatic alkenes could be oxidized to afford ketones and aldehydes under clean, mild conditions with a first row, biorelevant metal catalyst. Moreover, the protocol shows a very good functional group tolerance. Mechanistic investigation suggests that Mn-oxo species, including an asymmetric, mixed-valent bis(μ-oxo)-Mn(III,IV) complex, are involved in the oxidation, and the solvent methanol participates in O2 activation that leads to the formation of the oxo species.
Radical-mediated aerobic oxidation of substituted styrenes and stilbenes
Aman, Hasil,Chiu, Wei-Hua,Chuang, Gary Jing,Liu, Pin-Heng
supporting information, p. 20103 - 20106 (2021/12/02)
A 2,2-azobis(isobutyronitrile)-catalyzed oxidative cleavage of alkenes with molecular oxygen as the oxidant was described. Carbonyl compounds and oxiranes were obtained in moderate yield under mild conditions. This study provided useful insights into the mechanism of aerobic oxidative cleavage of alkenes.
