1
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Das A, Mohit, Thomas KRJ. Donor-Acceptor Covalent Organic Frameworks as a Heterogeneous Photoredox Catalyst for Scissoring Alkenes to Carbonyl Constituents. J Org Chem 2023; 88:14065-14077. [PMID: 37695568 DOI: 10.1021/acs.joc.3c01594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
The conversion of alkenes to carbonyl constituents via the cleavage of the C═C bond is unique due to its biological and pharmacological significance. Though a number of oxidative C═C cleavage protocols have been demonstrated for terminal and electron-rich alkene systems, none of them were optimized for electron-deficient and conjugated alkenes. In this work, a covalent organic framework containing triphenylamine and triazine units was revealed to cleave the C═C bond of alkenes under very mild conditions involving visible light irradiation due to its photoredox property. The alkenes can be conveniently broken across the double bond to their constituent carbonyl derivatives on light irradiation in the presence of air and the covalent organic framework photocatalyst. This protocol is applicable for a wide range of alkenes in an aqueous acetonitrile medium with high functional group tolerance and regioselectivity. Though the electron-deficient alkenes required tetramethylethylene diamine as a sacrificial donor, the electron-rich alkenes do not demand any additives.
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Affiliation(s)
- Anupam Das
- Organic Materials Laboratory, Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Mohit
- Organic Materials Laboratory, Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - K R Justin Thomas
- Organic Materials Laboratory, Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India
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2
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Selective Styrene Oxidation Catalyzed by Phosphate Modified Mesoporous Titanium Silicate. CHEMISTRY 2023. [DOI: 10.3390/chemistry5010042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Selective oxidation of organics over an efficient heterogeneous catalyst under mild liquid phase conditions is a very demanding chemical reaction. Herein, we first report the modification of the surface of mesoporous silica MCM-41 material by phosphate for the efficient incorporation of Ti(IV) in the silica framework to obtain highly ordered 2D hexagonal mesoporous material STP-1. STP-1 has been synthesized by using tetraethyl orthosilicate, triethyl phosphate, and titanium isopropoxide as Si, P, and Ti precursors, respectively, in the presence of cationic surfactant cetyltrimethylammonium bromide (CTAB) under hydrothermal conditions. The observed specific surface area and pore volume of STP-1 were 878 m2g−1 and 0.75 ccg−1, respectively. Mesoporous STP-1 has been thoroughly characterized by XRD, FT-IR, Raman spectroscopy, SEM, and TEM analyses. Titanium incorporation (Ti/Si = 0.006) was confirmed from the EDX analysis. This mesoporous STP-1 was used as a heterogeneous catalyst for the selective oxidation of styrene into benzaldehye in the presence of dilute aqueous H2O2 as an oxidizing agent. Various reaction parameters such as the reaction time, the reaction temperature, and the styrene/H2O2 molar ratio were systematically studied in this article. Under optimized reaction conditions, the selectivity of benzaldehyde could reach up to 93.8% from styrene over STP-1. Further, the importance of both titanium and phosphate in the synthesis of STP-1 for selective styrene oxidation was examined by comparing the catalytic result with only a phosphate-modified mesoporous silica material, and it suggests that both titanium and phosphate synergistically play an important role in the high selectivity of benzaldehyde in the liquid phase oxidation of styrene.
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3
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Pardeshi S, Pownthurai B, Ganesan G, Keshari H, Jadhav Y, Chaskar A. Selective oxidation of vinylbenzenes & acyloins in the presence of silver catalyst using molecular oxygen as terminal oxidant. Tetrahedron Lett 2023. [DOI: 10.1016/j.tetlet.2023.154409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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4
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Ayed C, Yin J, Landfester K, Zhang KAI. Visible-Light-Promoted Switchable Selective Oxidations of Styrene Over Covalent Triazine Frameworks in Water. Angew Chem Int Ed Engl 2023; 62:e202216159. [PMID: 36708519 DOI: 10.1002/anie.202216159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/05/2023] [Accepted: 01/25/2023] [Indexed: 01/29/2023]
Abstract
Using photocatalytic oxidation to convert basic chemicals into high value compounds in environmentally benign reaction media is a current focus in catalytic research. The challenge lies in gaining controllability over product formation selectivity. We design covalent triazine frameworks as heterogeneous, metal-free, and recyclable photocatalysts for visible-light-driven switchable selective oxidation of styrene in pure water. Selectivity in product formation was achieved by activation or deactivation of the specific photogenerated oxygen species. Using the same photocatalyst, by deactivation of photogenerated H2 O2 , benzaldehyde was obtained with over 99 % conversion and over 99 % selectivity as a single product. The highly challenging and sensitive epoxidation of styrene was carried out by creating peroxymonocarbonate as an initial epoxidation agent in the presence of bicarbonate, which led to formation of styrene oxide with a selectivity up to 76 % with near quantitative conversion. This study demonstrates a preliminary yet interesting example for simple control over switchable product formation selectivity for challenging oxidation reactions of organic compounds in pure water.
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Affiliation(s)
- Cyrine Ayed
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Jie Yin
- Department of Materials Science and and State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, 200433, P. R. China
| | - Katharina Landfester
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Kai A I Zhang
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany.,Department of Materials Science and and State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, 200433, P. R. China
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5
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Liu T, Xue F, Wang B, Wang R, Cao W, Zhao X, Xia Y, Jin W, Zhang Y, Lin H, Liu C. Rapid microwave synthesis of Bi2WO6 for C=C bonds oxidative cleavage to ketones with visible light irradiation in aerobic micellar medium. J Catal 2022. [DOI: 10.1016/j.jcat.2022.11.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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6
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Liu T, Xue F, Chen Z, Cheng Z, Cao W, Wang B, Jin W, Xia Y, Zhang Y, Liu C. Bi4O5Br2 catalyzed selective oxidative of C=C double bonds to ketones with molecular oxygen under visible-light irradiation. J Catal 2022. [DOI: 10.1016/j.jcat.2022.08.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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7
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Liu A, Lin W, Ping S, Guan W, Hu N, Zheng S, Ren Y. Analysis of degradation and pathways of three common antihistamine drugs by NaClO, UV, and UV-NaClO methods. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:43984-44002. [PMID: 35122640 DOI: 10.1007/s11356-022-18760-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/15/2022] [Indexed: 06/14/2023]
Abstract
Antihistamines (ANTs) are medicines to treat allergic diseases. They have been frequently detected in the natural water environment, posing potential threats to the ecological environment and human health. In this study, the degradation of three common antihistamines, loratadine, fexofenadine, and cetirizine, was estimated under different oxidation methods (NaClO, UV, and UV-NaClO). The results showed that UV-NaClO had the highest degree of degradation on the drugs under most conditions: 100% degradation for fexofenadine within 20 s at pH 7 and 10. Under UV irradiation, the degradation efficiencies of the three drugs during 150 s were all above 77% at a pH of 7. The drugs' removal by NaClO was much lower than that of the previous two methods. In addition, this study explored the contribution rates of active oxygen species in the photolysis process. Among them, the contribution of 1O2 to the fexofenadine and cetirizine removal rate reached 70%. Different aqueous matrices (HCO3-, NO3-, and humic acid) had varying degrees of influence on the degradation. Acute toxicity tests and ultraviolet scans of the degradation products showed that the drugs were not completely mineralized, and the toxicities of the intermediates were even higher than those of the parent drugs. There were 9, 8, and 10 chloride oxidation products of loratadine, fexofenadine, and cetirizine, respectively, and 8 photolysis products of cetirizine were identified. For cetirizine, it was found that there were three identical intermediates produced by photodegradation and NaClO oxidation.
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Affiliation(s)
- Anchen Liu
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Panyu District, Guangzhou, 510006, People's Republic of China
| | - Wenting Lin
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Panyu District, Guangzhou, 510006, People's Republic of China
| | - Senwen Ping
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Panyu District, Guangzhou, 510006, People's Republic of China
| | - Wenqi Guan
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Panyu District, Guangzhou, 510006, People's Republic of China
| | - Ningyi Hu
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Panyu District, Guangzhou, 510006, People's Republic of China
| | - Sichun Zheng
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Panyu District, Guangzhou, 510006, People's Republic of China
| | - Yuan Ren
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Panyu District, Guangzhou, 510006, People's Republic of China.
- The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou, 510006, People's Republic of China.
- The Key Laboratory of Environmental Protection and Eco-Remediation of Guangdong Regular Higher Education Institutions, Guangzhou, 510006, People's Republic of China.
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Fernandes RA, Kumar P, Bhowmik A, Gorve DA. Regioselective Disulfide-Catalyzed Photocatalytic Oxidative Cleavage of 1-Arylbutadienes to Cinnamaldehydes. Org Lett 2022; 24:3435-3439. [PMID: 35466681 DOI: 10.1021/acs.orglett.2c00884] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This work discloses a simple, efficient, and environmentally benevolent disulfide-catalyzed photocatalytic regioselective oxidative cleavage of 1-arylbutadienes to cinnamaldehydes. This methodology illustrates mild reaction conditions, ambient temperature, excellent regioselectivity, and compatibility with wide range of functional groups (38 examples). The method gains significance, as few reports with limited substrate scope are available for such excellent photocatalytic oxidative cleavage of conjugated dienes.
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Affiliation(s)
- Rodney A Fernandes
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra, India
| | - Praveen Kumar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra, India
| | - Amit Bhowmik
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra, India
| | - Dnyaneshwar A Gorve
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra, India
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9
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Catalyst-Controlled Selectivity in Oxidation of Olefins: Highly Facile Success to Functionalized Aldehydes and Ketones. Catal Letters 2022. [DOI: 10.1007/s10562-021-03903-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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10
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11
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Hall MR, Moggach SA, Low PJ. Syntheses and Structures of trans-bis(Alkenylacetylide) Ruthenium Complexes. Chem Asian J 2021; 16:3385-3403. [PMID: 34468081 DOI: 10.1002/asia.202100850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 08/25/2021] [Indexed: 11/08/2022]
Abstract
A series of ruthenium alkenylacetylide complexes trans-[Ru{C≡CC(=CH2 )R}Cl(dppe)2 ] (R=Ph (1 a), c C4 H3 S (1 b), 4-MeS-C6 H4 (1 c), 3,3-dimethyl-2,3-dihydrobenzo[b]thiophene (DMBT) (1 d)) or trans-[Ru{C≡C-c C6 H9 }Cl(dppe)2 ] (1 e) were allowed to react with the corresponding propargylic alcohol HC≡CC(Me)R(OH) (R=Ph (A), c C4 H3 S (B), 4-MeS-C6 H4 (C), DMBT (D) or HC≡C-c C6 H10 (OH) (E) in the presence of TlBF4 and DBU to presumably give alkenylacetylide/allenylidene intermediates trans-[Ru{C≡CC(=CH2 )R}{C=C=C(Me)}(dppe)2 ]PF6 ([2]PF6 ). These complexes were not isolated but deprotonated to give the isolable bis(alkenylacetylide) complexes trans-[Ru{C≡CC(=CH2 )R}2 (dppe)2 ] (R=Ph (3 a), c C4 H3 S (3 b), 4-MeS-C6 H4 (3 c), DMBT (3 d)) and trans-[Ru{C≡C-c C6 H9 }2 (dppe)2 ] (3 e). Analogous reactions of trans-[Ru(CH3 )2 (dmpe)2 ], featuring the more electron-donating 1,2-bis(dimethylphosphino)ethane (dmpe) ancillary ligands, with the propargylic alcohols A or C and NH4 PF6 in methanol allowed isolation of the intermediate mixed alkenylacetylide/allenylidene complexes trans-[Ru{C≡CC(=CH2 )R}{C=C=C(Me)}(dmpe)2 ]PF6 (R=Ph ([4 a]PF6 ), 4-MeS-C6 H4 ([4 c]PF6 ). Deprotonation of [4 a]PF6 or [4 c]PF6 gave the symmetric bis(alkenylacetylide) complexes trans-[Ru{C≡CC(=CH2 )R}2 (dmpe)2 ] (R=Ph (5 a), 4-MeS-C6 H4 (5 c)), the first of their kind containing the dmpe ancillary ligand sphere. Attempts to isolate bis(allenylidene) complexes [Ru{C=C=C(Me)R}2 (PP)2 ]2+ (PP=dppe, dmpe) from treatment of the bis(alkenylacetylide) species 3 or 5 with HBF4 ⋅ Et2 O were ultimately unsuccessful.
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Affiliation(s)
- Michael R Hall
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
| | - Stephen A Moggach
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
| | - Paul J Low
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
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12
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Upadhyay R, Kumar S, Maurya SK. V
2
O
5
@TiO
2
Catalyzed Green and Selective Oxidation of Alcohols, Alkylbenzenes and Styrenes to Carbonyls. ChemCatChem 2021. [DOI: 10.1002/cctc.202100654] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Rahul Upadhyay
- Chemical Technology Division CSIR-Institute of Himalayan Bioresource Technology Palampur Himachal Pradesh 176 061 India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad 201 002 India
| | - Shashi Kumar
- Chemical Technology Division CSIR-Institute of Himalayan Bioresource Technology Palampur Himachal Pradesh 176 061 India
| | - Sushil K. Maurya
- Chemical Technology Division CSIR-Institute of Himalayan Bioresource Technology Palampur Himachal Pradesh 176 061 India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad 201 002 India
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13
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Yu T, Guo M, Wen S, Zhao R, Wang J, Sun Y, Liu Q, Zhou H. Poly(ethylene glycol) dimethyl ether mediated oxidative scission of aromatic olefins to carbonyl compounds by molecular oxygen. RSC Adv 2021; 11:13848-13852. [PMID: 35423908 PMCID: PMC8697527 DOI: 10.1039/d1ra02007b] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 04/05/2021] [Indexed: 12/16/2022] Open
Abstract
A simple, and practical oxidative scission of aromatic olefins to carbonyl compounds using O2 as 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. A simple and practical O2 oxidized scission of monosubstituted, gem- and 1,2-disubstituted, trisubstituted and tetrasubstituted aromatic olefins to aldehydes and ketones in PEGDME has been developed.![]()
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Affiliation(s)
- Tao Yu
- Research Center of Green Pharmaceutical Technology and Process, Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University Yichang 443002 China
| | - Mingqing Guo
- Research Center of Green Pharmaceutical Technology and Process, Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University Yichang 443002 China
| | - Simiaomiao Wen
- Research Center of Green Pharmaceutical Technology and Process, Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University Yichang 443002 China
| | - Rongrong Zhao
- Research Center of Green Pharmaceutical Technology and Process, Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University Yichang 443002 China
| | - Jinlong Wang
- Research Center of Green Pharmaceutical Technology and Process, Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University Yichang 443002 China
| | - Yanli Sun
- Research Center of Green Pharmaceutical Technology and Process, Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University Yichang 443002 China
| | - Qixing Liu
- Research Center of Green Pharmaceutical Technology and Process, Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University Yichang 443002 China
| | - Haifeng Zhou
- Research Center of Green Pharmaceutical Technology and Process, Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University Yichang 443002 China
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14
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He S, Li H, Chen X, Krylov IB, Terent'ev AO, Qu L, Yu B. Advances of N-Hydroxyphthalimide Esters in Photocatalytic Alkylation Reactions. CHINESE J ORG CHEM 2021. [DOI: 10.6023/cjoc202105041] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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15
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Ou J, He S, Wang W, Tan H, Liu K. Highly efficient oxidative cleavage of olefins with O2 under catalyst-, initiator- and additive-free conditions. Org Chem Front 2021. [DOI: 10.1039/d1qo00175b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Without employing any external catalyst, initiator and additives, an efficient and eco-friendly protocol has been developed for the synthesis of carbonyl compound via 1,4-dioxane- promoted oxidation of olefins with atmospheric O2 as the sole oxidant.
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Affiliation(s)
- Jinhua Ou
- Department of Material and Chemical Engineering
- Hunan Institute of Technology
- Hengyang
- China
- Key Laboratory of Chemo/Biosensing and Chemometrics
| | - Saiyu He
- Department of Material and Chemical Engineering
- Hunan Institute of Technology
- Hengyang
- China
| | - Wei Wang
- Department of Material and Chemical Engineering
- Hunan Institute of Technology
- Hengyang
- China
| | - Hong Tan
- Department of Material and Chemical Engineering
- Hunan Institute of Technology
- Hengyang
- China
| | - Kaijian Liu
- Hunan Provincial Engineering Research Center for Ginkgo biloba
- Hunan University of Science and Engineering
- Yongzhou 425100
- China
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16
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Ali D, Panday AK, Choudhury LH. Hydrogen Peroxide-Mediated Rapid Room Temperature Metal-Free C(sp 2)-H Thiocyanation of Amino Pyrazoles, Amino Uracils, and Enamines. J Org Chem 2020; 85:13610-13620. [PMID: 33054213 DOI: 10.1021/acs.joc.0c01738] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A rapid metal- and additive-free room temperature method for C(sp2)-H thiocyanation of aminopyrazoles, aminoisoxazole, aminoisothiazole, amino uracils, and aliphatic enamines has been developed in an aqueous medium using hydrogen peroxide as a benign oxidant and ammonium thiocyanate as a thiocyanating agent. On the other hand, the reaction of hydrogen peroxide and ammonium thiocyanate followed by one-pot addition of NaOH provides the corresponding disulfides in the case of amino azoles, and pyrimidine-fused 2-amino thiazoles were observed in the case of aminouracils. The salient features of this method are the use of an eco-friendly oxidant, reaction tunability to access different products, wide substrate scope, and good to very good yields.
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Affiliation(s)
- Danish Ali
- Department of Chemistry, Indian Institute of Technology Patna, Bihta, Patna 801106, India
| | - Anoop Kumar Panday
- Department of Chemistry, Indian Institute of Technology Patna, Bihta, Patna 801106, India
| | - Lokman H Choudhury
- Department of Chemistry, Indian Institute of Technology Patna, Bihta, Patna 801106, India
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17
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1,1,1,3,3,3-Hexafluoroisopropanol as an efficient medium for the room temperature oxidation of styrenes to benzaldehydes. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.152527] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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18
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Photo-mediated selective deconstructive geminal dihalogenation of trisubstituted alkenes. Nat Commun 2020; 11:4462. [PMID: 32901002 PMCID: PMC7479597 DOI: 10.1038/s41467-020-18274-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/12/2020] [Indexed: 12/14/2022] Open
Abstract
Selective deconstructive functionalization of alkenes, other than the well-established olefin metathesis and ozonolysis, to produce densely functionalized molecular scaffolds is highly attractive but challenging. Here we report an efficient photo-mediated deconstructive germinal dihalogenation of carbon-carbon double bonds. A wide range of geminal diiodoalkanes and bromo(iodo)alkanes (>40 examples) are directly prepared from various trisubstituted alkenes, including both cyclic and acyclic olefins. This C=C cleavage is highly chemoselective and produces geminal dihalide ketones in good yields. Mechanistic investigations suggest a formation of alkyl hypoiodites from benzyl alcohols and N-iodoimides, which undergo light-induced homolytic cleavage to generate active oxygen radical species. Efficient synthetic pathways to geminal dihalides are quite limited, despite their versatility as chemical building blocks. Here, the authors report a photo-mediated deconstructive fragmentation of cyclic and acyclic trisubstituted alkenes to access a variety of geminal dihalides.
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19
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Du L, Wang Z, Wu J. Iodobenzene-catalyzed oxidative cleavage of olefins to carbonyl compounds. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.152204] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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20
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Visible-light-promoted oxidative decarboxylation of arylacetic acids in air: Metal-free synthesis of aldehydes and ketones at room temperature. CHINESE CHEM LETT 2020. [DOI: 10.1016/j.cclet.2019.12.031] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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