- Calcium Complexation by α-Hydroxy Ketones. Characterization of a Calcium Complex of Phenacyl Alcohol
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Solution and solid-state structural data are presented for a discrete complex of phenacyl alcohol with calcium chloride, (2+)*2Cl(-)*H2O, in which phenacyl alcohol serves as a bidentate ligand, with coordination of calcium to both the carbonyl oxygen and the hydroxyl group.This constitutes the first structural characterization of a calcium complex with the important pharmacophoric α-hydroxy ketone functionality.
- Doxsee, Kenneth M.,Ferguson, Cynthia M.,Wash, Paul L.,Saulsbery, Robin L.,Hope, Hakon
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- Mechanistic Insights into the Formation of δ-Lactones by Cerium-Catalyzed Aerobic Coupling of β-Oxoesters with Enol Acetates
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δ-Valerolactone derivatives are formed by the cerium-catalyzed, aerobic coupling of β-oxoesters with enol acetates and dioxygen. The products possess a 1,4-diketone moiety, thus, the conversion can be regarded as an Umpolung since the β-oxoesters are oxidized to electrophilic α-radicals. The transformation has similarities to the Baeyer-Villiger oxidation (BVO) where the higher substituted residue migrates. An endoperoxidic oxycarbenium ion comparable to the Criegee intermediate in the BVO is proposed as a reaction intermediate in this case of the oxidative C?C coupling reaction, but in contrast to the BVO, the less substituted alkyl residue migrates. It was demonstrated by the conversion of β-oxoesters with two stereocenters that this 1,2-alkyl shift proceeds with retention of configuration. A radical chain mechanism of the coupling reaction was furthermore evidenced by the conversion of enol acetates and β-oxoesters with cyclopropyl substituents. Isolation and characterization of products with opened cyclopropane rings established the constitution of radical intermediates.
- Christoffers, Jens,Speldrich, Jean-Marico
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- The ortho-Difluoroalkylation of Aryliodanes with Enol Silyl Ethers: Rearrangement Enabled by a Fluorine Effect
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Presented herein is an intriguing effect of fluorine, and it allows difluoroenol silyl ethers to couple with aryliodanes in a redox-neutral manner to afford ortho-iodo difluoroalkylated arenes. The remaining iodide group provides a versatile platform for converting the products into various valuable difluoroalkylated arenes. The reaction shows excellent functional-group compatibility and broad substrate scope. A DFT mechanistic study suggests that the fluorine effect facilitates a subtle nucleophilic attack of the oxygen atom of enol silyl ethers onto aryliodanes, therefore leading to a rearrangement.
- Huang, Xin,Zhang, Yage,Zhang, Chaoshen,Zhang, Lei,Xu, Ying,Kong, Lichun,Wang, Zhi-Xiang,Peng, Bo
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- A comparative photomechanistic study (spin trapping, EPR spectroscopy, transient kinetics, photoproducts) of nucleoside oxidation (dG and 8-oxodG) by triplet-excited acetophenones and by the radicals generated from α-oxy-substituted derivatives through no
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The photooxidation of 2′-deoxyguanosine (dG) and its derivative 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) by a series of acetophenones (AP-X) and benzophenone (BP) has been studied. The favorable absorption characteristics of the benzoyl chromophore e
- Adam, Waldemar,Arnold, Markus A.,Nau, Werner M.,Pischel, Uwe,Saha-Moeller, Chantu R.
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- Iron-catalyzed ketonization of 2-aryl-1,1-dibromoalkenes with KOAc: Synthesis of α-acetoxy aryl ketones via a Michael-like addition process
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A novel and convenient iron-catalyzed ketonization of 2-aryl-1,1- dibromoalkenes with KOAc has been achieved. A series of α-acetoxy aryl ketones were prepared with moderate yields via 2-carbon position functionalization of 2-aryl-1,1-dibromoalkenes.
- Zhao, Ming,Kuang, Chun Xiang,Cheng, Xue Zhi,Yang, Qing
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- Conjugate Addition of Acyloxy Groups to Alkynylphenyliodonium Tetrafluoroborates under Both Basic and Acidic Conditions. Synthesis of α-Acyloxy Ketones
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Reaction of alkynylphenyliodonium tetrafluoroborates 1 with sodium salts of carboxylic acids in the presence of water affords α-acyloxy ketones.The reaction also proceeds under acidic conditions.The fact that the reaction of (4-hydroxy-1-butynyl)phenyliod
- Ochiai, Masahito,Kunishima, Munetaka,Fuji, Kaoru,Nagao, Yoshimitsu
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- Study on the reactive transient α-λ3-iodanyl- acetophenone complex in the iodine(III)/PhI(I) catalytic cycle of iodobenzene-catalyzed α-acetoxylation reaction of acetophenone by electrospray ionization tandem mass spectrometry
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RATIONALE Hypervalent iodine compounds are important and widely used oxidants in organic chemistry. In 2005, Ochiai reported the PhI-catalyzed α-acetoxylation reaction of acetophenone by the oxidation of PhI with m-chloroperbenzoic acid (m-CPBA) in acetic acid. However, until now, the most critical reactive α-λ3-iodine alkyl acetophenone intermediate (3) had not been isolated or directly detected. METHODS Electrospray ionization tandem mass spectrometry (ESI-MS/MS) was used to intercept and characterize the transient reactive α-λ3- iodine alkyl acetophenone intermediate in the reaction solution. RESULTS The trivalent iodine species was detected when PhI and m-CPBA in acetic acid were mixed, which indicated the facile oxidation of a catalytic amount of PhI(I) to the iodine(III) species by m-CPBA. Most importantly, 3·H+ was observed at m/z 383 from the reaction solution and this ion gave the protonated α-acetoxylation product 4·H+ at m/z 179 in MS/MS by an intramolecular reductive elimination of PhI. CONCLUSIONS These ESI-MS/MS studies showed the existence of the reactive α-λ3-iodine alkyl acetophenone intermediate 3 in the catalytic cycle. Moreover, the gas-phase reactivity of 3·H+ was consistent with the proposed solution-phase reactivity of the α-λ3-iodine alkyl acetophenone intermediate 3, thus confirming the reaction mechanism proposed by Ochiai. Copyright
- Wang, Hao-Yang,Zhou, Juan,Guo, Yin-Long
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- Electrochemical Synthesis of Fluorinated Ketones from Enol Acetates and Sodium Perfluoroalkyl Sulfinates
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The electrochemical synthesis of fluorinated ketones from enol acetates and RfSO2Na in an undivided cell under constant current conditions was developed. The electrosynthesis proceeded via perfluoroalkyl radical generation from sodium perfluoroalkyl sulfinate followed by addition to the enol acetate and transformation of the resulting C radical to a fluorinated ketone. The method is applicable to a wide range of enol acetates and results in the desired products in yields of 20 to 85%.
- Vil’, Vera A.,Merkulova, Valentina M.,Ilovaisky, Alexey I.,Paveliev, Stanislav A.,Nikishin, Gennady I.,Terent’ev, Alexander O.
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supporting information
p. 5107 - 5112
(2021/06/30)
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- A Unified Approach for Divergent Synthesis of Heterocycles via TMSOTf-Catalyzed Formal [3+2] Cycloaddition of Electron-Rich Alkynes
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We present a synthetic protocol for the construction of polysubstituted five-membered heterocycles via TMSOTf-catalyzed formal [3+2] cycloaddition of electron-rich alkynes, which features free from any metal, atom economy and water as the main by-product. Furthermore, alkenyl ether adduct has been verified as the key intermediate. Notably, by utilizing this approach, we can synthesize a broad range of polysubstituted furans, thiophenes and pyrroles, and extend this transformation to deliver fused-polyheterocycles. This reaction can be achieved on a gram scale and the corresponding products are intermediates for producing diverse potentially useful scaffolds. (Figure presented.).
- Chen, Ping,Cao, Wei,Li, Xiangqian,Shi, Dayong
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supporting information
p. 4789 - 4794
(2021/09/02)
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- Decarboxylative Oxyacyloxylation of Propiolic Acids: Construction of Alkynyl-Containing α-Acyloxy Ketones
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Novel decarboxylative oxyacyloxylation of propiolic acids has been developed. This reaction provides an efficient access to alkynyl-containing α-acyloxy ketones from readily available starting materials and exhibits significant functional group tolerance. Furthermore, oxyacyloxylation of terminal alkynes and aliphatic propiolic acids was also developed. A possible reaction mechanism is proposed based on mechanistic studies.
- Chen, Xin,Xin, Yangchun,Zhao, Zhi-Wei,Hou, Yu-Jian,Wang, Xiang-Xiang,Xia, Wen-Jin,Li, Ya-Min
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supporting information
p. 8216 - 8225
(2021/06/28)
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- Sulfur-mediated difunctionalization of internal and terminal alkynes for the synthesis of α-acetoxy ketones
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The sulfur-mediated difunctionalization of alkynes is reported to give α-acetoxy ketones in a one-pot operation under mild conditions with 19–92% yield. By using wet potassium acetate as both the aqueous base and nucleophilic reagent, both terminal alkynes and internal alkynes could be converted into the α-acetoxy ketone products.
- Li, Pingfan,Zhang, Zhong
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- Imidazolium-Based Ionic Network as a Robust Heterogeneous Catalyst in Synthesis of Phenacyl Derivatives
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A new imidazolium-based poly(ionic liquid) has been synthesized and used as a robust heterogeneous catalyst for the preparation of phenacyl derivatives by an SN2 reaction of different phenacyl bromides with a broad range of nucleophiles. The products are obtained in high yields under mild conditions. The catalyst can be recycled efficiently.
- Kakesh,Sayyahi,Badri,Tahanpesar
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p. 1218 - 1220
(2019/07/16)
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- Continuous-Flow Electrochemical Generator of Hypervalent Iodine Reagents: Synthetic Applications
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An efficient and reliable electrochemical generator of hypervalent iodine reagents has been developed. In the anodic oxidation of iodoarenes to hypervalent iodine reagents under flow conditions, the use of electricity replaces hazardous and costly chemical oxidants. Unstable hypervalent iodine reagents can be prepared easily and coupled with different substrates to achieve oxidative transformations in high yields. The unstable, electrochemically generated reagents can also easily be transformed into classic bench-stable hypervalent iodine reagents through ligand exchange. The combination of electrochemical and flow-chemistry advantages largely improves the ecological footprint of the overall process compared to conventional approaches.
- Elsherbini, Mohamed,Winterson, Bethan,Alharbi, Haifa,Folgueiras-Amador, Ana A.,Génot, Célina,Wirth, Thomas
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supporting information
p. 9811 - 9815
(2019/06/24)
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- Metal-Free Amidation Reactions of Terminal Alkynes with Benzenesulfonamide
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A novel and efficient approach has been developed to synthesize α-sulfonylamino ketones through the reaction between terminal alkynes and sulfonamides under ambient air using PIDA (diacetoxy iodobenzene). A library of α-sulfonylamino ketone derivatives having a variety of substituents has been synthesized. A plausible reaction pathway has been predicted. This reaction offers a broad substrate scope, metal-free synthesis, excellent regioselectivity, easily accessible reactants, and room temperature reaction conditions under ambient air and is operationally simple. A gram-scale synthesis demonstrates the potential applications of the present method. In addition, we have also synthesized α-acetoxy ketones in the case of absence of sulfonamide.
- Mahato, Sachinta,Santra, Sougata,Zyryanov, Grigory V.,Majee, Adinath
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- Efficient Aliphatic C?H Bond Oxidation Catalyzed by Manganese Complexes with Hydrogen Peroxide
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A tetradentate nitrogen ligand containing a benzimidazole ring and an electron-rich pyridine ring was developed, the resulting manganese complex exhibited good activity in the C?H oxidation of simple alkanes. In particular, cyclic aliphatic alkanes were transformed into ketones in very good yields (up to 89 %) by using environmentally benign H2O2 as the terminal oxidant. This protocol was also applied successfully in benzylic C?H oxidation, giving the corresponding ketones with very good selectivities. In addition, tertiary C?H bond oxidation of complex molecules by the manganese complex showed potential utility for assembling alcohols with good selectivity in late-stage chemical synthesis.
- Wang, Wenfang,Xu, Daqian,Sun, Qiangsheng,Sun, Wei
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supporting information
p. 2458 - 2464
(2018/04/02)
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- Oxidative α-Acetoxylation of a β-Oxime Ester with (Diacetoxyiodo)benzene Catalyzed by ScIII Salts: An Approach to the Docetaxel Side Chain
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Hypervalent iodine(III) compounds have emerged as reagents of choice for α-oxidation of various ketones under mild reaction conditions. We report herein a simple method for α-hydroxylation of a β-oxime ester, which involves an oxidative α-acetoxylation us
- Miyamoto, Kazunori,Hoque, Md. Mahbubul,Senoh, Yuhki,Ali, Mohammad Idrish,Nemoto, Hisao,Mandai, Tadakatsu
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supporting information
p. 2841 - 2845
(2018/06/21)
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- Electrocatalytic Dehydrogenative Esterification of Aliphatic Carboxylic Acids: Access to Bioactive Lactones
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A scalable and efficient electrocatalytic dehydrogenative esterification is reported. With an indirect electrolysis strategy, both intra- and intermolecular-type reactions were amenable to this practical method. With n-Bu4NI as the catalyst, un
- Zhang, Sheng,Lian, Fei,Xue, Mengyu,Qin, Tengteng,Li, Lijun,Zhang, Xu,Xu, Kun
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supporting information
p. 6622 - 6625
(2017/12/26)
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- PhI(OAc)2-promoted umpolung acetoxylation of enamides for the synthesis of α-acetoxy ketones
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Umpolung is a fundamental concept in organic chemistry, which provides an alternative strategy for the synthesis of target compounds which were not easily accessible by conventional methods. Herein, a mild and efficient PhI(OAc)2-promoted umpolung acetoxylation reactions of enamides was developed for the synthesis of α-acetoxy ketones. The reaction tolerates a wide range of functional groups and affords α-acetoxy ketones in good to excellent yields. PhI(OAc)2 serves as a source of acetoxy in the reaction.
- Chen, Ming,Zhang, Wei,Ren, Zhi-Hui,Gao, Wen-Yun,Wang, Yao-Yu,Guan, Zheng-Hui
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p. 761 - 768
(2017/06/05)
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- Integration of aqueous biphasic with magnetically recyclable systems: Polyethylene glycol-grafted Fe3O4 nanoparticles catalyzed phenacyl synthesis in water
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The present work trends to define an efficient phenacyl catalytic synthesis method employing a new nano-magnetite-supported organocatalyst. Polyethylene glycol (PEG) was bonded successfully onto silica coated ferrite and the resultant nanoparticles (PEG@SiO2@Fe3O4) characterized by fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), thermal gravimetric analysis (TGA), vibrating sample magnetometry (VSM), energy dispersive X-ray analysis (EDAX) and X-ray diffraction (XRD) that exhibited a good catalytic activity in the reaction. The nanoparticles could be easily separated from the reaction mixture by an external magnet and reused in seven reaction cycles without significant loss of activity.
- Amini, Atefeh,Sayyahi, Soheil,Saghanezhad, Seyyed Jafar,Taheri, Narges
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- Palladium-Catalyzed Chemo- and Enantioselective C?O Bond Cleavage of α-Acyloxy Ketones by Hydrogenolysis
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A chemoselective C?O bond cleavage of the ester alkyl side-chain of α-acyloxy ketones was realized for the first time by a highly efficient palladium-catalyzed hydrogenolysis (S/C=6000, the highest catalytic efficiency by far). Furthermore, a kinetic resolution of α-acyloxy ketones was first developed by enantioselective hydrogenolysis with good yields and up to 99 % ee.
- Chen, Jianzhong,Zhang, Zhenfeng,Liu, Delong,Zhang, Wanbin
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supporting information
p. 8444 - 8447
(2016/07/19)
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- Novel and efficient transformation of enamides into α-acyloxy ketones via an acyl intramolecular migration process
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Hydrogen peroxide and anhydride mediated transformation of enamides to afford substituted α-acyloxy ketones is described. This transition-metal-free cascade reaction has a broad substrate scope and high efficiency. The acyl intramolecular migration procedure successfully achieved this acyloxylation process under mild conditions and increased the atom efficiency.
- Zhou, Xiaoqiang,Ma, Haojie,Cao, Jinhui,Liu, Xingxing,Huang, Guosheng
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supporting information
p. 10070 - 10073
(2016/11/06)
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- NHPI and ferric nitrate: A mild and selective system for aerobic oxidation of benzylic methylenes
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A mild and selective system comprising N-hydroxyphthalimide (NHPI) and Fe(NO3)3·9H2O was developed for the oxidation of benzylic methylenes with an atmospheric pressure of molecular oxygen at 25°C. The influences of reaction conditions such as solvent, different metal catalysts and catalyst loading were studied, as well as the kinetics of the oxidation reaction. Various benzylic methylene substrates could be oxidized to the corresponding carbonyl compounds in satisfactory yields with this catalytic system. Hammett analysis suggested that the substrates with electron-donating groups would have higher oxidation rates. Isotopic (18O) labeling experiments provided evidence of the participation of the nitrate anion in the catalytic cycle. In addition, a possible radical mechanism involving hydrogen atom abstraction by PINO (phthalimide-N-oxyl) and nitrate participation for the oxidation of benzylic methylenes in the Fe(NO3)3·9H2O/NHPI/O2 system was proposed.
- Miao, Chengxia,Zhao, Hanqing,Zhao, Quanyi,Xia, Chungu,Sun, Wei
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p. 1378 - 1383
(2016/03/08)
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- Visible Light Mediated Reductive Cleavage of C-O Bonds Accessing α-Substituted Aryl Ketones
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C-O σ-bonds in multifaceted benzoin derivatives can be effectively cleaved as acetates using catalytic amounts of [Ru(bpy)3]Cl2 as photoredox catalyst in combination with Hantzsch ester and triethylamine as a sacrificial electron donor. This mild and operationally simple method is applicable to a great variety of substrates. Homo- and cross-benzoins, which are easily accessed by NHC (N-heterocyclic carbene) catalysis, with both electron-withdrawing and electron-donating substituents, including aryl halogenides, can be employed. The deoxygenated counterparts are isolated in good to excellent yields. These broadly accessible, α-substituted (nonsymmetric) aryl ketones are versatilely applicable for further transformations as illustrated by the syntheses of 2-arylbenzofurans.
- Speckmeier, Elisabeth,Padié, Clément,Zeitler, Kirsten
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supporting information
p. 4818 - 4821
(2015/10/12)
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- Iron-Catalyzed Dioxygenation of Alkenes and Terminal Alkynes by using (Diacetoxyiodo)benzene as Oxidant
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An iron-catalyzed syn-diacetoxylation of alkenes and 1,2-oxyacetoxylation of terminal alkynes has been developed using (diacetoxyiodo)benzene as oxidant. A broad range of internal and terminal alkenes, including electron-rich as well as electron-deficient alkenes, gave the desired products in good to excellent yields with high diastereoselectivity (up to >99:1 dr). In addition the high catalytic activity of iron catalysis for the 1,2-oxyacetoxylation of terminal alkynes is also reported. The roles of catalyst, oxidant and other reaction parameters were evaluated for activation of the unsaturated bond.
- Srinivas,Rawat, Vikas S.,Sreedhar, Bojja
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supporting information
p. 3587 - 3596
(2016/01/25)
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- Stereoselective one-pot synthesis of β-alkylsulfide enol esters. Base-triggered rearrangement under mild conditions
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A stereoselective one-pot procedure was developed to prepare S-substituted (Z)-enol esters through a base-triggered rearrangement. This transition metal-free multicomponent approach can be performed under an air atmosphere at room temperature, tolerates a wide set of chemical functionalities and generally affords high isolated yields. The (Z)-selectivity arises from the [1,4]-S- to O-acyl migration. the Partner Organisations 2014.
- Heredia, Adrian A.,Soria-Castro, Silvia M.,Bouchet, Lydia M.,Oksdath-Mansilla, Gabriela,Barrionuevo, Cecilia A.,Caminos, Daniel A.,Bisogno, Fabricio R.,Argueello, Juan E.,Penenory, Alicia B.
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p. 6516 - 6526
(2014/08/18)
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- Flexible stereoselective functionalizations of ketones through umpolung with hypervalent iodine reagents
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The functionalization of carbonyl compounds in the α-position has gathered much attention as a synthetic route because of the wide biological importance of such products. Through polarity reversal, or "umpolung", we show here that typical nucleophiles, such as oxygen, nitrogen, and even carbon nucleophiles, can be used for addition reactions after tethering them to enol ethers. Our findings allow novel retrosynthetic planning and rapid assembly of structures previously accessible only by multistep sequences. A Nu approach: An efficient α-functionalization of ketones with a range of simple and useful nucleophiles is possible by using hypervalent iodine reagents (see scheme; Nu′ can be the Nu itself or a protected form of this nucleophile group).
- Mizar, Pushpak,Wirth, Thomas
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p. 5993 - 5997
(2014/06/10)
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- I2-catalyzed regioselective oxo- and hydroxy-acyloxylation of alkenes and enol ethers: A facile access to α-acyloxyketones, esters, and diol derivatives
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I2-catalyzed oxo-acyloxylation of alkenes and enol ethers with carboxylic acids providing for the high yield synthesis of α-acyloxyketones and esters is described. This unprecedented regioselective oxidative process employs TBHP and Et3/s
- Reddi, Rambabu N.,Prasad, Pragati K.,Sudalai, Arumugam
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supporting information
p. 5674 - 5677
(2015/02/19)
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- Cu-iminopyridine complexes as catalysts for carbene and nitrene transfer reactions
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Copper complexes with chiral iminopyridine ligands were screened for their catalytic efficiency in carbene (cyclopropanation) and nitrene transfer reactions (aziridination, CH amidation). Both pre-formed and in situ formed complexes were considered. The r
- Abedi, Yaghoub,Biffis, Andrea,Gava, Riccardo,Tubaro, Cristina,Chelucci, Giorgio,Stoccoro, Sergio
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p. 512 - 516
(2014/07/07)
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- Silver acetate mediated acetoxylations of alkyl halides
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Silver acetate promotes the acetoxylation of alkyl halides under neutral reaction conditions. The reaction is applicable to primary and activated secondary alkyl halides, and 2,2-dibromoacetophenones for preparing the corresponding acetates in good yields. The presence of ester, amide, nitrile, hydroxy, and OTBDMS functions on the substrate is tolerated.
- Nolla-Saltiel, Roberto,Carrillo-Arcos, Ulises Alonso,Porcel, Susana
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supporting information
p. 165 - 169
(2014/03/21)
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- Efficient benzylic and aliphatic C-H oxidation with selectivity for methylenic sites catalyzed by a bioinspired manganese complex
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A benzimidazole-based nonheme manganese complex efficiently catalyzes benzylic, aliphatic C-H as well as tertiary C-H oxidation with hydrogen peroxide as the oxidant in the presence of acetic acid as additive. 18O labeling experiments suggest the reaction may proceed via a high-valent manganese-oxo intermediate.
- Shen, Duyi,Miao, Chengxia,Wang, Shoufeng,Xia, Chungu,Sun, Wei
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supporting information
p. 1108 - 1111
(2014/03/21)
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- Palladium-catalyzed asymmetric hydrogenation of α-acyloxy-1- arylethanones
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First hand: The first example of a palladium-catalyzed asymmetric hydrogenation of α-acyloxy ketones (1) was accomplished to give the hydrogenated products 2 with by far the highest catalytic efficiency in up to quantitative conversions and excellent enantioselectivities. The hydrogenated products could serve as important intermediates for the preparation of many drug candidates. TFE=2,2,2-trifluoroethanol. Copyright
- Chen, Jianzhong,Liu, Delong,Butt, Nicholas,Li, Chao,Fan, Dongyang,Liu, Yangang,Zhang, Wanbin
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supporting information
p. 11632 - 11636
(2013/11/06)
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- Straightforward and highly efficient synthesis of α-acetoxy ketones through gold-catalyzed intermolecular oxidation of terminal alkynes
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A variety of terminal alkynes were efficiently converted into the corresponding α-acetoxy ketones through gold-catalyzed intermolecular oxidation in the presence of 8-methylquinoline 1-oxide as the oxidant. The reaction probably proceeds through an α-oxo gold carbene intermolecular O-H insertion.
- Wu, Chao,Liang, Zhiwu,Yan, Dong,He, Weimin,Xiang, Jiannan
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p. 2605 - 2611
(2013/09/24)
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- Silver(I)-catalyzed reaction of terminal alkynes with (diacetoxyiodo) benzene: A convenient, efficient and clean preparation of α-acetoxy ketones
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Silver(I)-catalyzed reaction of terminal alkynes with (diacetoxyiodo) benzene in wet acetonitrile at room temperature afforded the corresponding α-acetoxy ketones in 55-93% yields. The salient features of this reaction are the effective utilization of PhI
- Deng, Guisheng,Luo, Jing
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p. 5937 - 5944
(2013/07/27)
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- Synthesis of a wide range of thioethers by indium triiodide catalyzed direct coupling between alkyl acetates and thiosilanes
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An indium triiodide-catalyzed substitution of the acetoxy group in alkyl acetates with thiosilanes provides access to a variety of thioethers. The method is efficient for a wide scope of acetates such as primary alkyl, secondary alkyl, tertiary alkyl, allylic, benzylic, and propargylic acetates.
- Nishimoto, Yoshihiro,Okita, Aya,Yasuda, Makoto,Baba, Akio
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supporting information; experimental part
p. 1846 - 1849
(2012/06/18)
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- β-cyclodextrin immobilized onto dowex resin: A unique microvessel and heterogeneous catalyst in nucleophilic substitution reactions
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The catalytic activity of β-cyclodextrin immobilized on Dowex resin as an efficient solid-liquid phase transfer catalyst was developed for the synthesis of alkyl thiocyanates and phenacyl derivatives in water. The nucleophilic substitution reactions were performed under mild reaction condition and gave the products in excellent yields. Furthermore, the catalyst could be recycled by facile separation without any loss of activity.
- Kiasat, Ali Reza,Zarinderakht, Nasrollah,Sayyahi, Soheil
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experimental part
p. 699 - 702
(2012/05/05)
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- Activity of 6-aryl-pyrrolo[2,3-d]pyrimidine-4-amines to Tetrahymena
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A series 6-aryl-pyrrolo[2,3-d]pyrimidine-4-amines (43 compounds), some of which are epidermal growth factor tyrosine kinase inhibitors, were tested for their protozoal toxicity using an environmental Tetrahymena strain as model organism. The protozoacidal activity of the analogues was found to be highly dependent on a 4-hydroxyl group at the 6-aryl ring, and a chiral 1-phenylethanamine substituent in position 4. Further, the potency was affected by the aromatic substitution pattern of the phenylethanamine: the unsubstituted, the meta-fluoro and the para-bromo substituted derivatives had the lowest minimum protozoacidal concentrations (8-16 μg/mL). Surprisingly, both enantiomers were found to have high potency suggesting that this compound class could have several modes of action. No correlation was found between the compounds protozoacidal activity and the in vitro epidermal growth factor receptor tyrosine kinase inhibitory potency. This suggests that the observed antimicrobial effects are related to other targets. Testing towards a panel of kinases indicated several alternative modes of action.
- Kaspersen, Svein Jacob,Hoff, Bard Helge,Sundby, Eirik,Charnock, Colin
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p. 35 - 41,7
(2020/07/30)
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- A sustainable byproduct catalyzed domino strategy: Facile synthesis of α-formyloxy and acetoxy ketones via iodination/nucleophilic substitution/hydrolyzation/oxidation sequences
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The sustainable byproduct catalyzed domino strategy has been performed for the facile synthesis of α-formyloxy and acetoxy ketones via iodination/nucleophilic substitution/hydrolyzation/oxidation sequences from simple and readily available aromatic ketone
- Zhu, Yan-Ping,Gao, Qing-He,Lian, Mi,Yuan, Jing-Jing,Liu, Mei-Cai,Zhao, Qin,Yang, Yan,Wu, An-Xin
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supporting information; experimental part
p. 12700 - 12702
(2012/01/03)
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- Iodine(III)-mediated α-acetoxylation of aromatic ketones
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In the presence of iodobenzene diacetate with potassium iodide, aromatic α-phenoxy ketones underwent α-acetoxylation to afford corresponding α-acetoxy ketones smoothly at room temperature in moderate to good yields.
- Tang, Jiansheng,Zheng, Min,Chen, Yao,Guo, Cancheng
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experimental part
p. 346 - 348
(2011/10/02)
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- Redox catalysis of halide ion for formal cross-dehydrogenative coupling: Bromide ion-catalyzed direct oxidative α-acetoxylation of ketones
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A novel catalytic approach for formal cross-dehydrogenative coupling using the redox property of bromide ion is reported. Simple bromide salts MBr can work as catalyst for direct oxidative α-acetoxylation of ketones.
- Nagano, Takashi,Jia, Zhenhua,Li, Xingshu,Yan, Ming,Lu, Gui,Chan, Albert S. C.,Hayashi, Tamio
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supporting information; experimental part
p. 929 - 931
(2011/01/09)
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- Copper(II) and 2,2'-biimidazole-promoted novel reaction of 4,4,4-trifluoro-1-phenylbutane-1,3-diones with iodobenzene diacetate
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A new and efficient way was developed to carry out the reaction of 4,4,4-trifluoro-1-phenylbutane-1,3-dione with iodobenzene diacetate under the assistance of Cu(II) and 2,2'-biimidazole at a low temperature in excellent yield. 2-Acetoxyacetophenone was obtained unexpectedly.
- Zhou, Chunmei,Zeng, Runsheng,Zou, Jianping
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experimental part
p. 294 - 298
(2010/10/21)
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- Enzyme-catalysed approach to the preparation of triazole antifungals: synthesis of (-)-genaconazole
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The work describes a new enzyme-mediated approach to optically active epoxide (2R,3S)-6, which is an important key intermediate in the preparation of single enantiomers of chiral azole antifungals. The conversion of (2R,3S)-6 into (-)-genaconazole is reported as an example of its synthetic relevance.
- Acetti, Daniela,Brenna, Elisabetta,Fuganti, Claudio,Gatti, Francesco G.,Serra, Stefano
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experimental part
p. 2413 - 2420
(2010/03/24)
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- Tetraarylphosphonium salts as soluble supports for oxidative catalysts and reagents
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(Figure Presented) Tetraarylphosphonium (TAP)-supported DMSO, TEMPO, and DIB reagents were synthesized and used for the oxidation of alcohols, including Swern oxidation and for the R-acetoxylation of ketones. By taking advantage of the predictable solubility properties of the TAP unit, simple precipitation and filtration of the phosphonium moiety permit complete separation of the desired oxidation products. This paper describes the preparation of these three TAP-supported oxidative reagents and their activity in the aforementioned oxidative transformations. Furthermore, we have demonstrated that these reagents can be recycled directly when used in catalytic processes and following regeneration when used in stoichiometric processes. 2009 American Chemical Society.
- Roy, Marie-Noelle,Poupon, Jean-Christophe,Charette, Andre B.
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supporting information; experimental part
p. 8510 - 8515
(2009/12/28)
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- The reaction of terminal alkynes with PhI(OAc)2: a convenient procedure for the preparation of α-acyloxy ketones
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Treatment of terminal alkynes with PhI(OAc)2 in different acids at 70 °C provided the corresponding α-acyloxy ketones in good to excellent yields. A plausible mechanism has been proposed based on the experimental results.
- Mo, Dong-Liang,Dai, Li-Xin,Hou, Xue-Long
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supporting information; experimental part
p. 5578 - 5581
(2011/02/22)
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- One-pot synthesis of phenacyl esters from acetophenone, [Bmim]Br 3, and potassium salts of carboxylic acids under solvent-free conditions
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One-pot synthesis of phenacyl esters from acetophenone, [Bmim]Br3, and potassium salts of carboxylic acids under solvent-free conditions gave the corresponding phenacyl esters with excellent yields. Copyright Taylor & Francis Group, LLC.
- Le, Zhang-Gao,Xie, Zong-Bo,Xu, Jian-Ping
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experimental part
p. 743 - 747
(2009/06/28)
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- Biomimetic transfer hydrogenation of 2-alkoxy- and 2-aryloxyketones with iron-porphyrin catalysts
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In situ generated iron porphyrins are applied as homogeneous catalysts in the transfer hydrogenation of α-substituted ketones. Using 2-propanol as hydrogen donor various protected 1,2-hydroxyketones are reduced to the corresponding mono-substituted 1,2-di
- Enthaler, Stephan,Spilker, Bj?rn,Erre, Giulia,Junge, Kathrin,Tse, Man Kin,Beller, Matthias
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p. 3867 - 3876
(2008/09/20)
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- Phenacyl esters of acetic acid derivatives and their application for the synthesis of 2-oxo-4-phenyl-5-(phenylhydrazono)-2,5-dihydro-furan-3-derivatives
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(Chemical Equation Presented) Coupling of various substituted phenacyl acetates 1 and diazonium salts 3 was studied. If the phenacyl acetates were substituted by an electronaceptor group such as CN or COOEt 3-substituted phenyl-5-(phenyl-hydrazono)-5H-fur
- Melnicky, Radek,Kvapil, Lubomir,Slezar, Petr,Grepl, Martin,Hlavac, Jan,Lycka, Antonin,Hradil, Pavel
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scheme or table
p. 1437 - 1443
(2009/04/07)
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- One-pot synthesis of α-formyloxy ketones from enolizable ketones
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One-pot synthesis of α-formyloxy tones as well as α-acetoxy ketones from enolizable ketones and [hydroxy(tosyloxy) iodo] benzene (HTIB)/polymer supported [hydroxy(tosyloxy) iodo] benzene (PSHTIB) in N,N-dimethylformamide (DMF)/N, N-dimethylacetamide (DMA)
- Kumar, Sunil,Kumar, Ashok,Gupta, Rakesh K.,Kumar, Devinder
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p. 338 - 345
(2008/04/01)
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- A convenient and versatile method for the preparation of α-hydroxymethyl ketone derivatives from the corresponding allyl silyl ethers or allyl carboxylates
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The ozonolysis of 1-substituted allyl silyl ethers or 1-substituted allyl carboxylates followed by treatment with bases gave the corresponding α-silyloxymethyl- or α-acyloxymethyl-ketones in good yields. It is proposed to proceed via the corresponding α-silyloxy- or α-acyloxyaldehydes intermediates followed by 1,4-group migration. The results of theoretical calculations are applicable to explain the experimental results.
- Hon, Yung-Son,Wong, Ying-Chieh,Wu, Kuo-Jui
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experimental part
p. 896 - 914
(2009/12/06)
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- Triazabicyclodecene: An effective isotope exchange catalyst in CDCl 3
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(Chemical Equation Presented) We describe the first effective H/D exchange reaction with acidic substrates in CDCl3 at room temperature. The particularly mild reaction conditions involved (solvent, base, and temperature) allow the chemoselective deuteration of ketones over esters. An NMR study was conducted with the aim of rationalizing the results obtained in the presence of TBD as catalyst.
- Sabot, Cyrille,Kumar, Kanduluru Ananda,Antheaume, Cyril,Mioskowski, Charles
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p. 5001 - 5004
(2008/02/07)
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- Synthesis and biological evaluation of quinoline salicylic acids as P-selectin antagonists
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Leukocyte recruitment of sites of inflammation and tissue injury involves leukocyte rolling along the endothelial wall, followed by firm adherence of the leukocyte, and finally transmigration of the leukocyte across cell junctions into the underlying tissue. The initial rolling step is mediated by the interaction of leukocyte glycoproteins containing active moieties such as sialyl Lewisx (sLex) with P-selectin expressed on endothelial cells. Consequently, inhibition of this interaction by means of a small molecule P-selectin antagonist is an attractive strategy for the treatment of inflammatory diseases such as arthritis. High-throughput screening of the Wyeth chemical library identified the quinoline salicylic acid class of compounds (1) as antagonists of P-selectin, with potency in in vitro and cell-based assays far superior to that of sLex. Through iterative medicinal chemistry, we identified analogues with improved P-selectin activity, decreased inhibition of dihydrooratate dehydrogenase, and acceptable CYP profiles. Lead compound 36 was efficacious in the rat AIA model of rheumatoid arthritis.
- Kaila, Neelu,Janz, Kristin,DeBernardo, Silvano,Bedard, Patricia W.,Camphausen, Raymond T.,Tam, Steve,Tsao, Desirée H.H.,Keith Jr., James C.,Nickerson-Nutter, Cheryl,Shilling, Adam,Young-Sciame, Ruth,Wang, Qin
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- An efficient method for the α-acetoxylation of ketones
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α-Acetoxylation of ketones catalyzed by iodobenzene using 30% aqueous hydrogen peroxide and acetic anhydride as the oxidant is an effective and economical method for the preparation of a-acetoxy ketones. The reaction gave the products in good yields witho
- Sheng, Jinmei,Li, Xiaolong,Tang, Mingfang,Gao, Botao,Huang, Guosheng
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p. 1165 - 1168
(2008/02/03)
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- A simple synthetic protocol for oxidation of alkyl-arenes into ketones using a combination of HBr-H2O2
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A wide variety of alkyl- and cycloalkyl-arenes undergo benzylic C-H oxidation by employing a combination of 48% hydrogen bromide and 30% hydrogen peroxide in dichloromethane at room temperature. In addition, a chemoselective oxidation at the benzylic position is feasible by deactivating the aromatic ring using the same combination.
- Khan, Abu T.,Parvin, Tasneem,Choudhury, Lokman H.,Ghosh, Subrata
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p. 2271 - 2274
(2007/10/03)
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- Practical preparation of esters and thioacetates from alkyl halides and carboxylates or thioacetate catalyzed by PEG400 without solvent
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Carboxylic esters and thioacetates were conveniently prepared in good to excellent yields under mild conditions by the reaction of alkyl halides with sodium carboxylates or sodium thioacetate catalyzed by PEG400 in the absence of solvents. Copyright Taylor & Francis Group, LLC.
- Cao, Yu-Qing,Wu, Guo-Qiang,Li, Ya-Bin,Dai, Zhi,Chen, Bao-Hua
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p. 3353 - 3358
(2007/10/03)
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