- Transition metal-free oxidation of activated alcohols to aldehydes and ketones in 1,1,1,3,3,3-hexafluoro-2-propanol
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A simple and convenient procedure for the oxidation of various benzylic, allylic and some aliphatic alcohols to their corresponding carbonyl compounds is described using sodium hypochlorite as the oxidant in 1,1,1,3,3,3-hexafluoro-2- propanol without use
- Khaksar, Samad,Talesh, Saeed Mohammadzadeh
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- Controlled reduction of activated primary and secondary amides into aldehydes with diisobutylaluminum hydride
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A practical method is disclosed for the reduction of activated primary and secondary amides into aldehydes using diisobutylaluminum hydride (DIBAL-H) in toluene. A wide range of aryl and alkyl N-Boc, N,N-diBoc and N-tosyl amides were converted into the corresponding aldehydes in good to excellent yields. Reduction susceptible functional groups such as nitro, cyano, alkene and alkyne groups were found to be stable. Broad substrate scope, functional group compatibility and quick conversions are the salient features of this methodology.
- Azeez, Sadaf,Kandasamy, Jeyakumar,Sabiah, Shahulhameed,Sureshbabu, Popuri
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supporting information
p. 2048 - 2053
(2022/03/31)
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- C70Fullerene Catalyzed Photoinduced Aerobic Oxidation of Benzylamines to Imines and Aldehydes
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C70 fullerene catalyzed photoinduced oxidation of benzylic amines at ambient conditions has been explored here. The developed strategy's main feature includes the additive/oxidant-free conversion of benzylic amine to corresponding imine and aldehydes. The reaction manifests broad substrate scope with excellent function group leniency and is applicable up to the gram scale. Further, symmetrical secondary amines can also be synthesized from benzylic amine in a one-pot two-step process. Various experiments and density functional theory studies revealed that the current reaction involves the generation of reactive oxygen species, single electron transfer reaction, and benzyl radical formation as key steps under photocatalytic conditions.
- Kumar, Inder,Kumar, Rakesh,Gupta, Shiv Shankar,Sharma, Upendra
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supporting information
p. 6449 - 6457
(2021/05/29)
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- A novel selective oxidative cleavage of C–C bond mediated by black nickel oxide in the presence of molecular oxygen
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A selective aerobic oxidative cleavage of C–C bond is developed with black nickel oxide (NiOx) as the catalyst. For the oxidation of 1-phenyl-1, 2-ethanediol, a 97.5% conversion in 96.7% selectivity of benzaldehyde is obtained under 0.3 MPa of O2 at 140 °C for 3 h. The relationship between the catalytic performance of NiOx and structure is discussed. It is concluded that the existence of Ni3+ should be crucial to the activity of catalyst. Moreover, the recycling experiments showed that the catalyst can retain a high activity even after being reused for five times.
- Meng, Lingwu,Li, Wei,Guo, Pengfei,Wang, Shun,Tong, Xinli
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- Copper(II)-Ethanolamine Triazine Complex on Chitosan-Functionalized Nanomaghemite for Catalytic Aerobic Oxidation of Benzylic Alcohols
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Abstract: In this study a novel, effective and recoverable Cu(II)-catalyst was synthesized by incorporating of Cu(OAc)2 within ethanolamine-triazine derivative (TAETA) attached to chitosan (Chs)-functionalized γ-Fe2O3 nanoparticles [MNP@Chs/TAETA-Cu(II)]. It was characterized by different techniques such as FT-IR, EDS, ICP, TEM, TGA and VSM. The as-prepared nanocomposite demonstrated high oxidation activity and desired selectivity in the aerobic oxidation of structurally diverse set of benzyl alcohols. Spectral results and leaching experiments revealed that this magnetically recoverable heterogeneous catalyst preserved its structure after it was reused several?times. This protocol offers some beneficial features such as the use of oxygen as an ideal oxidant, stability of nanocomplex, easily catalyst separation by using an external magnetic field and efficient recycling as well as the lack of by-products. Graphic Abstract: [Figure not available: see fulltext.]
- Hasanpour, Benyamin,Jafarpour, Maasoumeh,Feizpour, Fahimeh,Rezaeifard, Abdolreza
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- Rapid, chemoselective and mild oxidation protocol for alcohols and ethers with recyclable N-chloro-N-(phenylsulfonyl)benzenesulfonamide
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Chlorine is the 20th most abundant element on the earth compared to bromine, iodine, and fluorine, a sulfonimide reagent, N-chloro-N-(phenylsulfonyl)benzenesulfonamide (NCBSI) was identified as a mild and selective oxidant. Without activation, the reagent was proved to oxidize primary and secondary alcohols as well as their symmetrical and mixed ethers to corresponding aldehydes and ketones. With recoverable PS-TEMPO catalyst, selective oxidation over chlorination of primary and secondary alcohols and their ethers with electron-donating substituents was achieved. The reagent precursor of NCBSI was recovered quantitatively and can be reused for synthesizing NCBSI.
- Badani, Purav,Chaturbhuj, Ganesh,Ganwir, Prerna,Misal, Balu,Palav, Amey
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supporting information
(2021/06/03)
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- Catalytic study of the copper-based magnetic nanocatalyst on the aerobic oxidation of alcohols in water
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A copper-based magnetic nanocatalyst has been prepared by co-precipitation method and characterized by FESEM, EDS, TEM, XRD, XRF, ICP–OES, FTIR, and BET analysis. This new nanocatalyst displays a good activity toward the aerobic oxidation of a wide range of alcohols in water. Moreover, it is recyclable up to five following runs by simple filtration without any significant loss of its catalytic activity.
- Dehkordi, S. Saeid Saei,Albadi, Jalal,Jafari, Abbas Ali,Samimi, Heshmat Allah
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p. 2527 - 2538
(2021/03/24)
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- Novel oxovanadium and dioxomolybdenum complexes of tridentate ONO-donor Schiff base ligand: Synthesis, characterization, crystal structures, Hirshfeld surface analysis, DFT computational studies and catalytic activity for the selective oxidation of benzyl
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Two new oxovanadium and dioxomolybdenum Schiff base complexes, [VvO(L)(OCH3)(CH3OH)] and [MoVIO2(L)(CH2CH3OH)], were synthesized by treating an ONO-donor type Schiff base ligand
- Amiri Rudbari, Hadi,Ashfaq, Muhammad,Behjatmanesh-Ardakani, Reza,Fallah-Mehrjardi, Mehdi,Forootan, Pooran,Kargar, Hadi,Nawaz Tahir, Muhammad,Shahzad Munawar, Khurram
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- Cu-Mn Bimetallic Complex Immobilized on Magnetic NPs as an Efficient Catalyst for Domino One-Pot Preparation of Benzimidazole and Biginelli Reactions from Alcohols
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An efficient magnetically recyclable bimetallic catalyst by anchoring copper and manganese complexes on the Fe3O4 NPs was prepared and named as Fe3O4@Cu-Mn. It was founded as a powerful catalyst for the domino one-pot oxidative benzimidazole and Biginelli reactions from benzyl alcohols as a green protocol in the presence of air, under solvent-free and mild conditions. Fe3O4@Cu-Mn NPs were well characterized by FT-IR, XRD, FE-SEM, TEM, VSM, TGA, EDX, DLS, and ICP analyses. The optimum range of parameters such as time, temperature, amount of catalyst, and solvent were investigated for the domino one-pot benzimidazole and Biginelli reactions to find the optimum reaction conditions. The catalyst was compatible with a variety of benzyl alcohols, which provides favorable products with good to high yields for all of derivatives. Hot filtration and Hg poisoning tests from the nanocatalyst revealed the stability, low metal leaching and heterogeneous nature of the catalyst. To prove the synergistic and cooperative effect of the catalytic system, the various homologues of the catalyst were prepared and then applied to a model reaction separately. Finally, the catalyst could be filtered from the reaction mixture simply, and reused for five consecutive cycles with a minimum loss in catalytic activity and performance. Graphic Abstract: A new magnetically recyclable Cu/Mn bimetallic catalyst has been developed for domino one-pot oxidation-condensation of benzimidazole and Biginelli reactions from alcohols. [Figure not available: see fulltext.]
- Nasseri, Mohammad Ali,Rezazadeh, Zinat,Kazemnejadi, Milad,Allahresani, Ali
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p. 1049 - 1067
(2020/09/11)
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- A novel two-dimensional metal-organic framework as a recyclable heterogeneous catalyst for the dehydrogenative oxidation of alcohol and theN-arylation of azole compounds
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A novel metal-organic framework (MOF) with two-dimensional (2D) crystal structure was developed using Cu(NO3)2·3H2O and 2,2′,5,5′-tetramethoxy-[1,1′-biphenyl]-4,4′-dicarboxylic acid. Further, its structure was characterized using infrared spectroscopy, thermogravimetry, X-ray diffraction, and X-ray crystallography. The activated Cu-MOF was used to catalyze the dehydrogenative oxidation of alcohol andN-arylation of azole compounds. Furthermore, it could be easily recovered and reused.
- Liu, Chengxin,Cui, Jin,Wang, Yufang,Zhang, Mingjie
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p. 11739 - 11744
(2021/03/31)
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- Zwitterion-induced organic-metal hybrid catalysis in aerobic oxidation
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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.
- Hu, Rong-Bin,Lam, Ying-Pong,Ng, Wing-Hin,Wong, Chun-Yuen,Yeung, Ying-Yeung
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p. 3498 - 3506
(2021/04/07)
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- Synthesis, spectral characterization, SC-XRD, HSA, DFT and catalytic activity of a dioxidomolybdenum complex with aminosalicyl-hydrazone Schiff base ligand: An experimental and theoretical approach
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A new dioxidomolybdenum(VI) complex has been successfully prepared by the reaction of an ONO donor Schiff base, derived by condensing 4-amino-2-hydroxybenzohydrazide and 3-methoxysalicylaldehyde, with MoO2(acac)2. The structures of s
- Kargar, Hadi,Fallah-Mehrjardi, Mehdi,Behjatmanesh-Ardakani, Reza,Munawar, Khurram Shahzad,Ashfaq, Muhammad,Tahir, Muhammad Nawaz
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- SBA-15 Supported Silver Catalyst for the Efficient Aerobic Oxidation of Toluene Under Solvent-Free Conditions
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The efficient SBA-15 supported silver catalysts(Ag/SBA-15) were prepared and characterized by ICP-OES, XRD, TEM, SEM, XPS and N2 adsorption–desorption techniques. The catalysts exhibited an excellent catalytic activity for the aerobic oxidation of toluene to benzaldehyde under solvent-free conditions. Conversion of toluene and selectivity of benzaldehyde were 50% and 89% respectively over catalyst with 9.1 wt% Ag loading (10Ag/SBA-15). A wide range of substrates were tolerated under the selected reaction conditions. The kinetic study shows that the oxidation of toluene over 10Ag/SBA-15 is pseudo-first-order reaction and the activation energy Ea is 45.1?kJ/mol. A plausible mechanism involving oxygen free radicals was proposed for the aerobic oxidation reaction. Compared with the traditional method, the newly designed heterogeneous catalytic system shows better economic applicability, environmental friendliness and broader application prospects. Graphical abstract: [Figure not available: see fulltext.]
- Chen, Lei,Chen, Yanjiao,Dai, Xuan,Guo, Jiaming,Peng, Xinhua
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- Core-shell Co-MOF-74@Mn-MOF-74 catalysts with Controllable shell thickness and their enhanced catalytic activity for toluene oxidation
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A series of core-shell Co-MOF-74@Mn-MOF-74 samples with different shell thicknesses were prepared by the seed growth method, which were characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), inductively coupled plasma mass spectrometry (ICP-MS), X-ray photoelectron spectroscopy, nitrogen adsorption-desorption and scanning electron microscopy (SEM). The shell thickness of these MOF samples were successfully controlled by adjusting the mass ratio between MnCl2·4H2O and Co-MOF-74. On this basis, these MOFs were applied to the catalytic oxidation of toluene. The results showed that with the growth of Mn-MOF-74 in the outer layer of Co-MOF-74, the oxidative selectivity of the substrate to benzaldehyde was greatly improved for the synergy between the core layer and shell layer. The conversion of toluene was 22.4%, and the selectivity of benzaldehyde was 98.1%. In addition, the catalyst can transform various substituted toluene into the corresponding aldehydes in highly selectivity and still keep good stability after four catalytic cycles. The selectivity of the corresponding aldehyde is generally above 80%.
- Gu, Xiangyu,Huang, Cheng,Xu, Zengchuang,Wu, Hao,Dong, Ruilan,Liu, Rui,Chen, Jing,Zhu, Hongjun
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- Samarium-based Grignard-type addition of organohalides to carbonyl compounds under catalysis of CuI
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Grignard-type additions were readily achieved under the mediation of CuI (10 mol%) and samarium (2 equiv.) by employing various organohalides,e.g.benzyl, aryl, heterocyclic and aliphatic halides (Cl, Br or I), and diverse carbonyl compounds (e.g.carbonic esters, carboxylic esters, acid anhydrides, acyl chlorides, ketones, aldehydes, propylene epoxides and formamides) to afford alcohols, ketones and aldehydes, respectively, with high efficiency and chemoselectivity, in which the organosamarium intermediate might be involved.
- Liu, Chen,Liu, Yongjun,Qi, Yan,Song, Bin,Wang, Liang,Xiao, Shuhuan
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supporting information
p. 6169 - 6172
(2021/06/30)
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- Selective oxidation of alkenes to carbonyls under mild conditions
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Herein, a practical and sustainable method for the synthesis of aldehydes, ketones, and carboxylic acids from an inexpensive olefinic feedstock is described. This transformation features very sustainable and mild conditions and utilizes commercially available and inexpensive tetrahydrofuran as the additive, molecular oxygen as the sole oxidant and water as the solvent. A wide range of substituted alkenes were found to be compatible, providing the corresponding carbonyl compounds in moderate-to-good yields. The control experiments demonstrated that a radical mechanism is responsible for the oxidation reaction.
- Huo, Jie,Xiong, Daokai,Xu, Jun,Yue, Xiaoguang,Zhang, Pengfei,Zhang, Yilan
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supporting information
p. 5549 - 5555
(2021/08/16)
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- Hydroxyl radical-mediated oxidative cleavage of CC bonds and further esterification reaction by heterogeneous semiconductor photocatalysis
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A hydroxyl radical-mediated aerobic cleavage of alkenes and further sequence esterification reaction for the preparation of carbonyl compounds have been developed by using tubular carbon nitride (TCN) as a general heterogeneous photocatalyst under an oxygen atmosphere with visible light irradiation. This protocol has an excellent substrate scope and gives the desired aldehydes, ketones and esters in moderate to high yields. Importantly, this metal-free procedure employed photogenerated hydroxyl radicals in situ as green oxidation active species, avoiding the present additional initiators. The reaction could be carried out under solar light irradiation and was applicable to large-scale reactions. Furthermore, the recyclable TCN catalyst could be used several times without a significant loss of activities.
- Hong, Mei,Jia, Rui,Miao, Hongyan,Ni, Bangqing,Niu, Tengfei,Wang, Hui
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p. 6591 - 6597
(2021/09/10)
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- Thiol-initiated photocatalytic oxidative cleavage of the C=C bond in olefins and its extension to direct production of acetals from olefins
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The oxidative cleavage of olefins to produce aldehydes/ketones is an important reaction in organic syntheses. In this manuscript, a mild and operationally simple protocol for the aerobic oxidation of olefins to produce carbonyl compounds was realized over ZnIn2S4under visible light, using air as the oxidant and a thiol as the initiator. It was proposed that the photogenerated holes over ZnIn2S4attack the thiol to produce thiyl radicals, which initiate the oxidative cleavage of the C=C bond in olefins to produce aldehydes/ketones. By further coupling with the condensation between the as-obtained aldehydes/ketones and alcohols, this strategy can also be applied to the production of different acetals directly from the olefins. This study demonstrates a new pathway to realize the oxidative cleavage of olefins to produce aldehydes/ketones, and also provides a new protocol for the production of acetals directly from the olefins.
- Wang, Xinglin,Li, Yuanyuan,Li, Zhaohui
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p. 1000 - 1006
(2021/02/26)
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- Visible-Light-Driven Oxidative Cleavage of Alkenes Using Water-Soluble CdSe Quantum Dots
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The oxidative cleavage of C=C bonds is an important chemical reaction, which is a popular reaction in the photocatalytic field. However, high catalyst-loading and low turnover number (TON) are general shortcomings in reported visible-light-driven reactions. Herein, the direct oxidative cleavage of C=C bonds through water-soluble CdSe quantum dots (QDs) is described under visible-light irradiation at room temperature with high TON (up to 3.7×104). Under the same conditions, water-soluble CdSe QDs could also oxidize sulfides to sulfoxides with 51–84 % yields and TONs up to 3.4×104. The key features of this photocatalytic protocol include high TONs, wide substrates scope, low catalyst loadings, simple and mild reaction conditions, and molecular O2 as the oxidant.
- Li, Jianing,Zhao, Jingnan,Ma, Cunfei,Yu, Zongyi,Zhu, Hongfei,Yun, Lei,Meng, Qingwei
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p. 4985 - 4992
(2021/10/16)
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- Nitrosoarene-Catalyzed HFIP-Assisted Transformation of Arylmethyl Halides to Aromatic Carbonyls under Aerobic Conditions
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A rare metal-free nucleophilic nitrosoarene catalysis accompanied by highly hydrogen-bond-donor (HBD) solvent, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), organocatalytically converts arylmethyl halides to aromatic carbonyls. This protocol offers an effective means to access a diverse array of aromatic carbonyls with good chemoselectivity under mild reaction conditions. The activation of arylmethyl halides by HFIP to generate stable carbocation and autoxidation of in situ generated hydroxylamine to nitrosoarene in the presence of atmospheric O2 are the keys to success.
- Pradhan, Suman,Sharma, Vishali,Chatterjee, Indranil
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supporting information
p. 6148 - 6152
(2021/08/03)
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- Rerouting the Organocatalytic Benzoin Reaction toward Aldehyde Deuteration
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Reactive intermediates are key to halting and promoting chemical transformations; however, due to their elusive nature, they are not straightforwardly harnessed for reaction design. Herein, we describe studies aimed at stabilizing reactive intermediates in the N-heterocyclic carbene (NHC) catalytic cycle, which enabled the full shutdown of the known benzoin coupling pathway, while rerouting its intermediates toward deuteration. The reversible nature of NHC catalysis and the selective stabilization of reaction intermediates facilitated clean hydrogen-deuterium exchange reactions of aromatic aldehydes by D2O, even for challenging electron-withdrawing substrates. In several cases, the addition of catalytic amounts of phenyl boronic acid was used to further stabilize highly reactive intermediates and mitigate the formation of benzoin coupling byproducts. The mechanistic understanding at the foundation of this work resulted in unprecedented mild conditions with base and catalyst loadings as low as 0.1 mol %, and a scalable deuteration reaction applicable to a broad substrate scope with outstanding functional group tolerance. More importantly, adopting this approach enabled the construction of a guideline for identifying the appropriate catalyst and conditions for different substrates. Experimental studies combined with machine learning and computational methods shed light on the nontrivial mechanistic underpinnings of this reaction.
- Gadekar, Santosh C.,Dhayalan, Vasudevan,Nandi, Ashim,Zak, Inbal L.,Mizrachi, Meital Shema,Kozuch, Sebastian,Milo, Anat
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p. 14561 - 14569
(2021/12/01)
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- METHOD FOR OXIDATIVE CLEAVAGE OF COMPOUNDS WITH UNSATURATED DOUBLE BOND
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A method for oxidative cleavage of a compound with an unsaturated double bond is provided. The method includes the steps of: (A) providing a compound (I) with an unsaturated double bond, a trifluoromethyl-containing reagent, and a catalyst; wherein, the catalyst is represented by Formula (II): M(O)mL1yL2z??(II);wherein, M, L1, L2, m, y, z, R1, R2 and R3 are defined in the specification; and(B) mixing the compound with an unsaturated double bond and the trifluoromethyl-containing reagent to perform an oxidative cleavage of the compound with the unsaturated double bond by using the catalyst in air or under oxygen atmosphere condition to obtain a compound represented by Formula (III):
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Paragraph 0071; 0077
(2021/07/10)
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- METHOD FOR OXIDATIVE CLEAVAGE OF COMPOUNDS WITH UNSATURATED DOUBLE BOND
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A method for oxidative cleavage of a compound with an unsaturated double bond is provided. The method comprises the following step: (A) providing a compound (I) with an unsaturated double bond, a reagent with trifluoromethyl, and a catalyst; wherein the catalyst is represented by the following formula (II): M(O)mL1yL2z (II); wherein, M, L1, L2, m, y, z, R1, R2 and R3 are defined in the specification; and (B) mixing the compound with an unsaturated double bond and the reagent with a trifluoromethyl to perform an oxidation of the compound with the unsaturated double bond by using the catalyst at air or an oxygen condition to get a compound presented as formula (III):
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Paragraph 0053-0054; 0062-0063
(2021/03/19)
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- Aerobic epoxidation of styrene over Zr-based metal-organic framework encapsulated transition metal substituted phosphomolybdic acid
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Catalytic epoxidation of styrene with molecular oxygen is regarded as an eco-friendly alternative to producing industrially important chemical of styrene oxide (STO). Recent efforts have been focused on developing highly active and stable heterogeneous catalysts with high STO selectivity for the aerobic epoxidation of styrene. Herein, a series of transition metal monosubstituted heteropolyacid compounds (TM-HPAs), such as Fe, Co, Ni or Cu-monosubstituted HPA, were encapsulated in UiO-66 frameworks (denoted as TM-HPA@UiO-66) by direct solvothermal method, and their catalytic properties were investigated for the aerobic epoxidation of styrene with aldehydes as co-reductants. Among them, Co-HPA@UiO-66 showed relatively high catalytic activity, stability and epoxidation selectivity at very mild conditions (313 K, ambient pressure), that can achieve 82 % selectivity to STO under a styrene conversion of 96 % with air as oxidant and pivalaldehyde (PIA) as co-reductant. In addition, the hybrid composite catalyst can also efficiently catalyze the aerobic epoxidation of a variety of styrene derivatives. The monosubstituted Co atoms in Co-HPA@UiO-66 are the main active sites for the aerobic epoxidation of styrene with O2/PIA, which can efficiently converting styrene to the corresponding epoxide through the activation of the in-situ generated acylperoxy radical intermediate.
- Hu, Dianwen,Song, Xiaojing,Zhang, Hao,Chang, Xinyu,Zhao, Chen,Jia, Mingjun
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- Heterogeneous carbon nitride photocatalyst for C-C bond oxidative cleavage of vicinal diols in aerobic micellar medium
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A green and efficient visible-light promoted aerobic oxidative C-C bond cleavage of vicinal diols in micellar medium has been developed. This protocol used graphitic carbon nitride with nitrogen vacancies (CN620) as a metal-free recyclable photocatalyst and CTAB as surfactant in water. Control experiments and the ESR results indicated that superoxide radicals and valence band holes played an important role in the reaction. Further isotope experiments suggested both a β-scission/HAT pathway and an oxidation/hydrolysis/dehydration pathway for the reaction, which is different from previous reports. The semiconductor/micellar catalyst system can be recycled at least 10 times without a significant reduction in activity. Furthermore, this reaction could be carried out under solar light irradiation and was applicable to large-scale reactions with similar results.
- Chen, Jiayang,Chen, Shengjun,Dong, Xinyu,Hong, Mei,Ni, Bangqing,Niu, Tengfei,Zhang, Tianhao
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supporting information
p. 5042 - 5049
(2020/08/25)
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- Rhodium-catalyzed reductive carbonylation of aryl iodides to arylaldehydes with syngas
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The reductive carbonylation of aryl iodides to aryl aldehydes possesses broad application prospects. We present an efficient and facile Rh-based catalytic system composed of the commercially available Rh salt RhCl3·3H2O, PPh3 as phosphine ligand, and Et3N as the base, for the synthesis of arylaldehydes via the reductive carbonylation of aryl iodides with CO and H2 under relatively mild conditions with a broad substrate range affording the products in good to excellent yields. Systematic investigations were carried out to study the experimental parameters. We explored the optimal ratio of Rh salt and PPh3 ligand, substrate scope, carbonyl source and hydrogen source, and the reaction mechanism. Particularly, a scaled-up experiment indicated that the catalytic method could find valuable applications in industrial productions. The low gas pressure, cheap ligand and low metal dosage could significantly improve the practicability in both chemical researches and industrial applications.
- Chen, Suqing,Liu, Zhenghui,Mu, Tiancheng,Wang, Peng,Yan, Zhenzhong,Yu, Dongkun,Zhao, Xinhui
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p. 645 - 656
(2020/05/14)
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- Cu(ii) vitamin C tunes photocatalytic activity of TiO2 nanoparticles for visible light-driven aerobic oxidation of benzylic alcohols
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The incorporation of Cu(OAc)2 into ascorbic acid coated TiO2 nanoparticles easily provided a new heterogeneous visible-light active titania-based photocatalyst (TiO2-AA-Cu(ii)) which was characterized by different techniques such as FT-IR, XPS, ICP-AES, TGA and TEM. A red-shift of the band-edge and a reduction of the band-gap (2.8 eV vs. 3.08 for TiO2) were demonstrated by UV-DRS and Tauc plots. The combination of the as-prepared TiO2-AA-Cu(ii) nanoparticles with TEMPO and molecular oxygen (air) afforded an active catalytic system for the selective oxidation of diverse set of benzylic alcohols under solvent-free conditions. A photoassisted pathway was confirmed for oxidation reactions evidenced by good correlation between apparent quantum yield (AQY) and diffuse reflectance spectra (DRS) of the as-prepared nanohybrid. The spectral data and recycling experiments demonstrated the structural stability of the title copper photocatalyst during oxidation reactions.
- Pourmorteza, Narges,Jafarpour, Maasoumeh,Feizpour, Fahimeh,Rezaeifard, Abdolreza
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p. 12053 - 12059
(2020/04/27)
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- Simple synthesis of the novel Cu-MOF catalysts for the selective alcohol oxidation and the oxidative cross-coupling of amines and alcohols
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A novel porous metal–organic framework {Cu2(bbda)0.5(Hbbda)1.5(OAc)1.5.8H2O} (UoB-5) was synthesized under ultrasound irradiation by employing a new Schiff base ligand H2bbda (4,4'(1,4-phenylene bis (azanylylidene)) bis (methanylylidene))dibenzoic acid) and was fully characterized. The microporous nature of UoB-5 was confirmed by gas-sorption measurements. This framework acted as a highly effective heterogeneous catalyst for the alcohol oxidation reaction with tert-butyl hydroperoxide (t-BuOOH) as an oxidant. The presence of coordinatively unsaturated metal sites in UoB-5 could be the reason for high performance in this reaction. Furthermore, using the long linker with the free -NC group and uncoordinated -N atom on the wall of the pores created UoB-5 an excellent candidate for the catalytic activities without activation of the framework. It was confirmed with the heterogeneous catalytic experiments on the one-pot tandem synthesis of imines from benzyl alcohols and anilines. Eventually, the new Cu-MOF (UoB-5) could be an alternative catalyst as a more economically favorable and environmentally friendly in the catalysis field.
- Ghamari Kargar, Pouya,Aryanejad, Sima,Bagherzade, Ghodsieh
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- A Remote ‘Imidazole’-Based Ruthenium(II) Para-Cymene Pre-catalyst for the Selective Oxidation Reaction of Alkyl Arenes and Alcohols
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Herein we disclosed the use of a remote ‘imidazole’-based precatalyst [(para-cymene)RuII(L)Cl]+, C-1 where L=2-(4-substituted-phenyl)-1H-imidazo[4,5-f][1,10] phenanthroline) for the selective oxidation of a variety of alkyl arenes/heteroarenes and alcohols to their corresponding aldehydes or ketones in presence of tert-butyl hydroperoxide (TBHP). The remote ‘imidazole’ moiety present in the complex facilitates the activation of oxidant and subsequent generation of active species via the release of para-cymene from C-1, which in-turn was less effective without the ‘imidazole’ moiety. The mechanistic features of C-1 promoted oxidation of alkyl arenes were also assessed from spectroscopic, kinetic, and few control experiments. The substrate scope for C-1 promoted oxidation reaction was assessed based on the selective oxidation of 27-different alkyl arenes/heteroarenes and 25 different alcohols to their corresponding aldehydes/ketones in moderate to good yields.
- Dutta, Manali,Bania, Kusum K.,Pratihar, Sanjay
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p. 926 - 932
(2020/03/05)
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- A Bifunctional Iron Nanocomposite Catalyst for Efficient Oxidation of Alkenes to Ketones and 1,2-Diketones
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We herein report the fabrication of a bifunctional iron nanocomposite catalyst, in which two catalytically active sites of Fe-Nx and Fe phosphate, as oxidation and Lewis acid sites, were simultaneously integrated into a hierarchical N,P-dual doped porous carbon. As a bifunctional catalyst, it exhibited high efficiency for direct oxidative cleavage of alkenes into ketones or their oxidation into 1,2-diketones with a broad substrate scope and high functional group tolerance using TBHP as the oxidant in water under mild reaction conditions. Furthermore, it could be easily recovered for successive recycling without appreciable loss of activity. Mechanistic studies disclose that the direct oxidation of alkenes proceeds via the formation of an epoxide as intermediate followed by either acid-catalyzed Meinwald rearrangement to give ketones with one carbon shorter or nucleophilic ring-opening to generate 1,2-diketones in a cascade manner. This study not only opens up a fancy pathway in the rational design of Fe-N-C catalysts but also offers a simple and efficient method for accessing industrially important ketones and 1,2-diketones from alkenes in a cost-effective and environmentally benign fashion.
- Ma, Zhiming,Ren, Peng,Song, Tao,Xiao, Jianliang,Yang, Yong,Yuan, Youzhu
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p. 4617 - 4629
(2020/05/19)
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- Spinel Structured Copper Ferrite Nano Catalyst with Magnetic Recyclability for Oxidative Decarboxylation of Phenyl Acetic Acids
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Abstract: A simple, efficient and environmentally benign method has been discussed for the synthesis of aldehydes and ketones by the oxidative decarboxylation of phenylacetic acid under ligand free condition using simple, efficient, preparatively easy, magnetically recoverable and low cost spinel CuFe2O4 nanoparticles. The catalyst was characterised using powder-XRD, FTIR, FE-SEM, EDX, VSM and HRTEM. The recyclability was examined and the results showed that the catalyst remained almost equally active up to five consecutive cycles. Graphic Abstract: Spinel Structured Copper Ferrite is a very efficient nano catalyst for Oxidative decarboxylation of Phenyl acetic acids and can be reused up to five cycles without significant loss in catalytic activity.[Figure not available: see fulltext.].
- Rahman, Taskia,Borah, Geetika,Gogoi, Pradip K.
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p. 2267 - 2272
(2020/02/18)
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- FeCl3-catalyzed oxidative decarboxylation of aryl/heteroaryl acetic acids: Preparation of selected API impurities
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There is an ever-increasing demand for impurity compounds for use in impurity profiling as regulatory agencies seek information during registration. Herein, we report the FeCl3-catalyzed oxidative decarboxylation of aryl- and heteroaryl acetic acids to the corresponding carbonyl compounds. A variety of useful aldehydes and ketones were prepared in a simple one-pot transformation by employing an environmentally benign, low-cost, and readily available iron salt. The utility of this method has been demonstrated by preparing five valuable API impurities including a multi-gram-scale synthesis of ketorolac impurity B for the first time. This journal is
- Gangadurai, Chinnakuzhanthai,Illa, Giri Teja,Reddy, D. Srinivasa
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p. 8459 - 8466
(2020/11/05)
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- One-pot, oxidative and selective conversion of benzylic silyl and tetrahydropyranyl ethers to gem-dichlorides using trichloroisocyanuric acid and triphenylphosphine as an efficient and neutral system
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A one-pot and oxidative method is described for the first time for the conversion of benzylic trimethylsilyl (TMS) and tetrahydropyranyl (THP) ethers to gem-dichlorides using trichloroisocyanuric acid (TCCA) and triphenylphosphine (PPh3) in neutral media. Various theses substrates containing electron withdrawing or donating groups can be efficiently converted to their corresponding gem-dichlorides in good to excellent yields. The present method shows a high degree of chemoselectivity, and due to its one-pot nature is in accordance with green chemistry.
- Khadem Moghaddam, Roqayeh,Aghapour, Ghasem
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p. 398 - 406
(2020/11/19)
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- Synthesis and structure activity relationships of cyanopyridone based anti-tuberculosis agents
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Mycobacterium tuberculosis, the causative agent of tuberculosis, relies on thymidylate kinase (MtbTMPK) for the synthesis of thymidine triphosphates and thus also DNA synthesis. Therefore, this enzyme constitutes a potential Achilles heel of the pathogen. Based on a previously reported MtbTMPK 6-aryl-substituted pyridone inhibitor and guided by two co-crystal structures of MtbTMPK with pyridone- and thymine-based inhibitors, we report the synthesis of a series of aryl-shifted cyanopyridone analogues. These compounds generally lacked significant MtbTMPK inhibitory potency, but some analogues did exhibit promising antitubercular activity. Analogue 11i demonstrated a 10-fold increased antitubercular activity (MIC H37Rv, 1.2 μM) compared to literature compound 5. Many analogues with whole-cell antimycobacterial activity were devoid of significant cytotoxicity.
- Boshoff, Helena I. M.,Caljon, Guy,Forbes, He Eun,Hulpia, Fabian,Jian, Yanlin,Munier-Lehmann, Héle?ne,Risseeuw, Martijn D. P.,Van Calenbergh, Serge
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- KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
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A novel and efficient protocol for chemoselective deacetylation under ambient conditions was developed using catalytic KMnO4. The stoichiometric use of KMnO4 highlighted the dual role of a heterogeneous oxidant enabling direct access to aromatic aldehydes in one-pot sequential deacetylation-oxidation. The reaction employed an alternative solvent system and allowed the clean transformation of benzyl acetate to sensitive aldehyde in a single step while preventing over-oxidation to acids. Use of inexpensive and readily accessible KMnO4 as an environmentally benign reagent and the ease of the reaction operation were particularly attractive, and enabled the controlled oxidation and facile cleavage of acetate in a preceding step. This journal is
- Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
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supporting information
p. 16702 - 16707
(2020/10/27)
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- Method for preparing aldehyde compounds through photocatalytic oxidation cracking β - hydroxyl compound C-C bond
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The invention provides a method for preparing aldehydes from C-C bonds of beta-hydroxy compounds by photocatalytic oxidative cracking. According to the method, the beta-hydroxy compounds are taken asa substrate, oxygen-containing gas is taken as an oxygen source, and C-C bond cracked products, namely, corresponding aldehydes can be generated under illumination in presence of a catalyst. The conditions are mild, the oxidation efficiency and the product yield are high, and the oxygen-containing gas is taken as the oxygen source under the illumination condition, so that the method is economical,environmentally friendly and green, meets the strategy of sustainable developed energy and has broad application prospect.
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Paragraph 0062-0063
(2020/07/29)
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- Iodobenzene-catalyzed oxidative cleavage of olefins to carbonyl compounds
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A metal-free approach for the oxidative cleavage of carbon–carbon double bonds of olefins to carbonyl compounds was established by using oxidant m-CPBA and non-metallic organocatalyst PhI in toluene/H2O. A broad scope of aromatic olefins was used. All the reactions proceeded smoothly at 35 °C in short reaction time to furnish the respective mono- and double carbonyl compounds selectively in moderate to good yields.
- Du, Lele,Wang, Zechao,Wu, Junliang
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supporting information
(2020/07/20)
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- Oxidative C-S Bond Cleavage of Benzyl Thiols Enabled by Visible-Light-Mediated Silver(II) Complexes
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The oxidative cleavage reaction of the C-S bond using singlet oxygen is challenging because of its uncontrollable nature. We have developed a novel method for the singlet-oxygen-mediated selective C-S bond cleavage reaction using silver(II)-ligand complexes. Visible-light-induced silver catalysis enables the controlled oxidative cleavage of benzyl thiols to afford carbonyl compounds, such as aldehydes or ketones, which are important synthetic components.
- Hong, Boseok,Aganda, Kim Christopher C.,Lee, Anna
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supporting information
p. 4395 - 4399
(2020/06/05)
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- Selective Solvent-Free and Additive-Free Oxidation of Primary Benzylic C–H Bonds with O2 Catalyzed by the Combination of Metalloporphyrin with N-Hydroxyphthalimide
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Abstract: A protocol for solvent-free and additive-free oxidation of primary benzylic C–H bonds with O2 was presented through adjusting the combination of metalloporphyrins and NHPI as binary catalysts to overcome the deficiencies encountered in current oxidation systems. The effects of reaction temperature, porphyrin structure, central metal, catalyst loading and O2 pressure were investigated systematically. For the optimized combination of T(2-OCH3)PPCo and NHPI, all the primary benzylic C–H bonds could be functionalized efficiently and selectively at 120 °C and 1.0?MPa O2 with aromatic acids as the primary products. The selectivity towards aromatic acids could reach up to 70–95% in the conversion of more than 30% for most of the substrates possessing primary benzylic C–H bonds in the metalloporphyrin loading of 0.012% (mol/mol). And the superior performance of T(2-OCH3)PPCo among the metalloporphyrins investigated was mainly attributed to its high efficiency in charge transfer and fewer positive charges around central metal Co (II) which favored the adduction of O2 to cobalt (II) forming the high-valence metal-oxo complex followed by the production of phthalimide N-oxyl radical (PINO) and the initiation of the catalytic oxidation cycle. This work would provide not only an efficient protocol in utilization of hydrocarbons containing primary benzylic C–H bonds, but also a significant reference in the construction of more efficient C–H bonds oxidation systems. Graphic Abstract: The solvent-free and additive-free oxidation of primary benzylic C–H bonds with O2 was presented through adjusting the combination of metalloporphyrins and NHPI as binary catalysts, and the highest selectivity towards aromatic acid reached up to 95.1% with the conversion of 88.5% in the optimized combination of T(2-OCH3)PPCo and NHPI.[Figure not available: see fulltext.].
- Shen, Hai-Min,Qi, Bei,Hu, Meng-Yun,Liu, Lei,Ye, Hong-Liang,She, Yuan-Bin
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p. 3096 - 3111
(2020/04/29)
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- Cercosporin-bioinspired selective photooxidation reactions under mild conditions
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The development of an efficient system for selective oxidation of organic compounds to generate more valuable compounds with molecular oxygen is a significant challenge in industrial chemistry. Bioinspired by the ability of naturally occurring perylenequinonoid pigments (PQPs) to generate reactive oxygen species (ROS) upon photoirradiation, here we report that cercosporin, one of the perylenequinonoid pigments, can function as a cost-effective and environmentally friendly photocatalyst for a wide range of selective oxidations, including benzylic C-H bonds to carbonyls, amines to aldehydes, and sulfides to sulfoxides. All of the representative reactions proceeded smoothly with high efficiency under mild conditions. Owing to the use of inexpensive metal-free visible light-driven photocatalyst produced from microbial fermentation with cheap glucose as the starting material and the ease of handling, we expect that this developed method will be particularly attractive for many more applications in synthetic transformation.
- Li, Jia,Bao, Wenhao,Tang, Zhaocheng,Guo, Baodang,Zhang, Shiwei,Liu, Haili,Huang, Shuping,Zhang, Yan,Rao, Yijian
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supporting information
p. 6073 - 6081
(2019/11/20)
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- Random Mutagenesis-Driven Improvement of Carboxylate Reductase Activity using an Amino Benzamidoxime-Mediated High-Throughput Assay
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Carboxylic acid reductases (CARs) catalyze the direct adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH) dependent reduction of carboxylic acids to their corresponding aldehydes. The identification and improvement of CARs by protein engineering is, however, severely limited by the lack of fast and generic methods to quantify aldehydes. Within this study, we applied a convenient high-throughput assay (HTA) based on amino benzamidoxime (ABAO) that allows the substrate-independent and chemoselective quantification of aldehydes. Random mutagenesis of the well-known CAR from Nocardia iowensis (CARNi) to improve its activity for sterically demanding 2-substituted benzoic acid derivatives was conducted in a KM-dependent fashion, and the HTA applied in the presence of microbial cells. The study identified a hot spot in the active site of CARNi that increased the affinity to 2-methoxybenzoic acid 9-fold upon mutation from glutamine to proline (Q283P). The catalytic performance of CARNiQ283P appeared to be significantly improved also for other substrates such as 2-substituted (2-Cl, 2-Br) as well as 3- and 4-substituted benzoic acids (3-OMe, 4-OMe), and even aliphatic octanoic acid. (Figure presented.).
- Schwendenwein, Daniel,Ressmann, Anna K.,Doerr, Mark,H?hne, Matthias,Bornscheuer, Uwe T.,Mihovilovic, Marko D.,Rudroff, Florian,Winkler, Margit
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supporting information
p. 2544 - 2549
(2019/04/26)
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- Copper Nanoparticles Immobilized on Nanocellulose: A Novel and Efficient Heterogeneous Catalyst for Controlled and Selective Oxidation of Sulfides and Alcohols
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In this work, we have described the versatility of low metal loading copper nanoparticles immobilized on nanocellulose for the controlled and selective oxidation of sulfides to sulfoxides and primary alcohols to aldehydes using green oxidant at room temperature. Aromatic, aliphatic and heterocyclic sulfides were oxidized to their corresponding sulfoxides with high yields without formation of over oxidized sulfones. Similarly, benzylic, allylic and aliphatic alcohols were selectively oxidized to aldehydes without traces of carboxylic acids in good to excellent yields.
- Dutta, Apurba,Chetia, Mitali,Ali, Abdul A.,Bordoloi, Ankur,Gehlot, Praveen S.,Kumar, Arvind,Sarma, Diganta
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p. 141 - 150
(2018/12/13)
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- Aerobic oxidation of alcohols with air catalyzed by decacarbonyldimanganese
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The oxidation of alcohols to carbonyl compounds using air as the terminal oxidant is highly desirable. As described in previous reports, the abstraction of α-H of the alcohol is the most important step, and it typically requires not only a metal catalyst but also complex ligands, co-catalysts and bases. Herein, we report a practical and efficient method for the oxidation of primary alcohols, secondary alcohols, 1,2-diols, 1,2-amino alcohols, and other α-functionalized alcohols using a commercially available catalyst, Mn2(CO)10, and no additives. Preliminary mechanistic studies indicated that an alkoxyl radical intermediate existed in our system, and a plausible mechanism consistent with the experimental results and literature was proposed.
- Meng, Shan-Shui,Lin, Li-Rong,Luo, Xiang,Lv, Hao-Jun,Zhao, Jun-Ling,Chan, Albert S. C.
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supporting information
p. 6187 - 6193
(2019/11/20)
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- Efficient selective oxidation of alcohols to aldehydes catalyzed by a morpholinone nitroxide
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Efficient chemoselective oxidation of primary alcohols to the corresponding aldehydes is described. The transformation is promoted by a catalytic morpholinone nitroxide radical catalyst which can be easily synthesized. A broad range of substrates includin
- Dong, Zhenhua,Gao, Pengwei,Xiao, Yongmei
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p. 3380 - 3388
(2019/11/05)
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- Switchable Bifunctional Bistate Reusable ZnO-Cu for Selective Oxidation and Reduction Reaction
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Herein we disclosed the utilization of copper loaded zinc oxide (ZnO-Cu) for its stimuli (O2/light) responsive switchable performance between its reduced (S-1) and oxidized (S-2) state for two antagonistic reactions, namely oxidation of alkyl arenes/heteroarenes to aldehydes/ketones and reduction of nitro arenes/heteroarenes to corresponding amines. The two states of the catalyst showed its switchable performance as highly active and poorly active catalyst for oxidation and reduction, and both reactions could be turned "off" and "on" by changing the stimuli (light and O2/N2). The switching efficiency between the states and their relative reactivity were found to be consistent under variety of reaction conditions and remain unaltered irrespective of oxidation-reduction (or vice versa) sequence and substrates used in the reaction. The photo catalysts (S-1 and S-2) demonstrated good catalytic activity, multiple reusability, broad substrate scope, and reasonable functional group tolerance for both the reactions and probed its quality performance in a large-scale setup. The system was used in an assisted tandem catalysis setup for the synthesis of benzyl amines utilizing both oxidation and reduction reaction by stimuli responsive switching between the states of the catalyst.
- Sarmah, Kasturi,Mukhopadhyay, Subhamoy,Maji, Tarun K.,Pratihar, Sanjay
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p. 732 - 745
(2019/01/11)
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- A transition metal free expedient approach for the C[dbnd]C bond cleavage of arylidene Meldrum's acid and malononitrile derivatives
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A transition metal free expedient approach for the C[dbnd]C bond cleavage of electron deficient alkenes such as arylidene Meldrum's acid and malononitrile derivatives are discussed. The C[dbnd]C bond of these compound were cleaved to benzoic acid in good yield at high temperature. Most importantly, with oxone in CH3CN/H2O at 45 °C or m-CPBA in DCM or NaClO2 in THF/H2O or PIDA in THF at room temperature furnished benzaldehyde derivatives selectively in excellent yields.
- Suresh, Muthiah,Kumari, Anusueya,Singh, Raj Bahadur
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- Oxygen-vacancies-engaged efficient carrier utilization for the photocatalytic coupling reaction
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Defects can greatly optimize the solar light harvesting capability and electronic structure of oxide materials. However, it remains challenging to achieve a defect engineering strategy under mild conditions. Meanwhile, the simultaneous exploitation of photogenerated holes (h+) and electrons (e?) to promote both photooxidation and photoreduction in a coupled system has rarely been reported. For the first time, we reveal an oxygen-vacancies-mediated photocatalytic strategy in which the electrons and holes are fully utilized for nitrobenzene reduction coupled with benzyl alcohol oxidation. The oxygen vacancies (OVs) generated in situ on the surface of TiO2 greatly extend light absorption into the visible region and promote the photogenerated electron transport for efficient photocatalysis. The experimental and theoretical results together indicate that chemisorption on the TiO2 surface decreases the oxidation potential of benzyl alcohol and causes an upward shift in its HOMO, which facilitates the oxidation reaction of benzyl alcohol to benzaldehyde. The in situ generated surface OVs also act as a bridge to enable the trapping and transferring of the photoinduced electrons to the nitrobenzene. This work provides a new perspective of utilizing the chemisorption between the reactant and catalyst to achieve a defect engineering strategy for synergetic photocatalysis.
- Yang, Xue,Tao, Huilin,Leow, Wan Ru,Li, Jingjun,Tan, Yanxi,Zhang, Yongfan,Zhang, Teng,Chen, Xiaodong,Gao, Shuiying,Cao, Rong
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p. 116 - 125
(2019/04/08)
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- Oxidative C-C bond formation and C-N bond cleavage catalyzed by complexes of copper(i) with acridine based (E N E) pincers (E = S/Se), recyclable as a catalyst
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Copper(i) complexes of 4,5-bis((phenylthio/seleno)methyl)acridine, [CuLBr] (C1 and C2) (L = L1/L2; pincer type (E N E) ligand), were synthesized and found to be thermally stable, and moisture and air insensitive. The complexes and ligands were characterized by multinuclei NMR and single crystal X-ray diffraction. In both complexes C1 and C2, ligands L1 and L2 coordinate with Cu in a pincer mode furnishing two six-membered chelate rings, with the distorted tetrahedral geometry of donor atoms around Cu. The Cu-S and Cu-Se bond lengths (?) are 2.2482(17)-2.2979(16) and 2.3603(14)-2.4177(13) respectively. These complexes served as efficient catalysts for cross dehydrogenative coupling of unactivated tertiary amines with unactivated terminal alkynes, and cleavage of the benzylic (C-N) bond of N,N dimethylbenzylamines under oxidative solvent-free conditions. The reactions were found to be highly selective, and no over-oxidation to acid was observed. A low catalytic loading of 1.0 mol% was good enough to bring about both these transformations with recyclability up to five times.
- Gupta, Sonu,Dubey, Pooja,Singh, Ajai K.,Jain, Nidhi
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p. 10129 - 10137
(2019/07/15)
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- Selective Functionalization of Styrenes with Oxygen Using Different Electrode Materials: Olefin Cleavage and Synthesis of Tetrahydrofuran Derivatives
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Electrode materials can have a significant impact on the course of an electrolysis reaction. Of particular interest is that different electrodes can generate different products from the same substrate. The electrode-material-selective transformations of styrene derivatives with molecular oxygen are reported. Platinum electrodes afford carbonyl products via cleavage of olefins, whereas tetrahydrofuran formation is achieved with carbon electrodes. A variety of different styrenes are available for both reactions. Electrolysis allows straightforward and mild chemical conversions that are metal- and oxidant-free. Electrochemical measurements illuminate the different effects of platinum and carbon electrodes on styrenes. The key to the differing reactions is probably that the oxidation potentials of the substrates are lower (higher HOMO energy) on carbon electrodes than on platinum electrodes. The adsorption of the substrates on carbon electrodes can also promote tetrahydrofuran formation.
- Imada, Yasushi,Okada, Yohei,Noguchi, Keiichi,Chiba, Kazuhiro
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supporting information
p. 125 - 129
(2018/12/05)
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