- Access to Triazolopiperidine Derivatives via Copper(I)-Catalyzed [3+2] Cycloaddition/Alkenyl C?N Coupling Tandem Reactions
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A copper-catalyzed [3+2] cylcoaddition/ alkenyl C?N coupling tandem reaction was demonstrated. It provided a method for the formation of triazolopiperidine skeletons. (Figure presented.).
- Xiao, Guorong,Wu, Kaifu,Zhou, Wei,Cai, Qian
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supporting information
p. 4988 - 4991
(2021/10/14)
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- Pre-carbonized nitrogen-rich polytriazines for the controlled growth of silver nanoparticles: Catalysts for enhanced CO2chemical conversion at atmospheric pressure
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High catalytic activity and sufficient durability are two unavoidable key indices of an efficient heterogeneous catalyst for the direct carboxylation of terminal alkynes with CO2 conversion. Nitrogen-rich covalent triazine frameworks (CTFs) are promising substrates, while random distribution of some residual -NH2 groups brings challenges to the controlled growth of catalytic species. Here, we adopt a pre-carbonization protocol, annealing below the carbonization temperature, to eliminate the random -NH2 groups in CTFs and meanwhile to promote polycondensation degree under the premise of maintaining the pore structure. Benefiting from the improved condensation and orderly N atoms, p-CTF-250, for which CTFs are annealed at 250 °C, exhibits improved CO2 adsorption capacity and the ability to control the growth of Ag NPs. Mono-dispersed Ag NPs are generated controllably and entrapped to form Ag@p-CTF-250 catalysts. These Ag@p-CTF-250 catalysts were employed in the direct carboxylation of various terminal alkynes with CO2 under mild conditions (50 °C, 1 atm) and showed excellent catalytic activity. In addition, these catalysts have robust recyclability and can be used for at least 5 catalytic runs while retaining yield above 90%. CO2 conversion proceeds well under the synergistic effect between the high CO2 capture capability and the uniform tiny Ag NPs in Ag@p-CTF-250 "nanoreactors". The results represent an efficient strategy for controlling the growth of metallic nanoparticles in porous organic polymer substrates containing disordered heteroatoms.
- Liu, Jian,Zhang, Xiaoyi,Wen, Bingyan,Li, Yipei,Wu, Jingjing,Wang, Zhipeng,Wu, Ting,Zhao, Rusong,Yang, Shenghong
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p. 3119 - 3127
(2021/05/25)
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- Gold-catalyzed homo- And cross-annulation of alkynyl carboxylic acids: a facile access to substituted 4-hydroxy 2: H -pyrones and total synthesis of pseudopyronine A
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A Au(i)-catalyzed homo- and cross-annulation reaction of alkynyl carboxylic acids offering 3,6-disubstituted 4-hydroxy 2H-pyrones has been demonstrated. The reaction tolerates various substituted alkynyl carboxylic acids and moderate to good yields of α-pyrone scaffolds have been observed. Later, a gram-scale reaction of the acid and the total synthesis of the natural product pseudopyronine A have been carried out successfully.
- Choudhary, Shivani,Gayyur,Ghosh, Nayan,Saxena, Anchal
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p. 8716 - 8723
(2020/11/17)
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- Extending the Salinilactone Family
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Five new members of the salinilactone family, salinilactones D–H, are reported. These bicyclic lactones are produced by Salinispora bacteria and display extended or shortened alkyl side chains relative to the recently reported salinilactones A–C. They were identified by GC/MS, gas chromatographic retention index, and comparison with synthetic samples. We further investigated the occurrence of salinilactones across six newly proposed Salinispora species to gain insight into how compound production varies among taxa. The growth-inhibiting effect of this compound family on multiple biological systems including non-Salinispora actinomycetes was analyzed. Additionally, we found strong evidence for significant cytotoxicity of the title compounds.
- Schlawis, Christian,Harig, Tim,Ehlers, Stephanie,Guillen-Matus, Dulce G.,Creamer, Kaitlin E.,Jensen, Paul R.,Schulz, Stefan
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p. 1629 - 1632
(2020/03/13)
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- Porous Carbon Nitride Frameworks Derived from Covalent Triazine Framework Anchored Ag Nanoparticles for Catalytic CO2 Conversion
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Porous carbon nitride frameworks (PCNFs) with uniform and rich nitrogen dopants and abundant porosity were successfully fabricated through the direct carbonization of the covalent triazine frameworks (CTFs) at different pyrolysis temperatures and used as supports to anchor and stabilize Ag nanoparticles (NPs) for catalytic CO2 conversion. Importantly, the pyrolysis temperature plays a crucial role in the properties of porous carbon nitride frameworks. The material carbonized at 700 °C showed the highest surface area and micro- and mesoporous structure with a certain interlayer distance. Taking advantage of their unique surface characteristics, PCNF-supported Ag NP catalysts (Ag/PCNF-T, T=pyrolysis temperature) were prepared by a simple chemical method. A series of characterizations revealed that Ag NPs are embedded in the porous carbon nitride frameworks and confined to a relatively small size with high dispersion owing to the assistance of the abundant surface groups and porous structures. The as-obtained Ag/PCNF-T catalysts, especially Ag/PCNF-700, showed excellent catalytic activity, selectivity, and stability for the carboxylation of CO2 with terminal alkynes under mild conditions. This can be due to the existence of abundant nitrogen atoms and diverse porosity, which resulted in highly efficient catalytic activity and stability.
- Lan, Xingwang,Li, Yiming,Du, Cheng,She, Tiantian,Li, Qing,Bai, Guoyi
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supporting information
p. 8560 - 8569
(2019/06/08)
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- Carboxylation of Terminal Alkynes with Carbon Dioxide Catalyzed by an In Situ Ag2O/N-Heterocyclic Carbene Precursor System
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A carboxylation of terminal alkynes with carbon dioxide (CO2) at ambient conditions was developed in situ using a series of N-heterocyclic carbene (NHC) precursors and Ag2O. The unique structure of NHCs largely increases the solubility of active Ag species and meanwhile activates CO2 by forming the NHC–CO2 adduct. This novel catalytic system demonstrated quite low Ag loading, very high activities, wide substrate generality and excellent tolerance for a variety of functionalities. In addition, avoiding cumbersome synthesis procedures, processing, and reserving of the photosensitive Ag complex, this system could be stored and operated as straightforward as the inorganic Ag salt catalysts.
- Yuan, Ye,Chen, Cheng,Zeng, Cheng,Mousavi, Bibimaryam,Chaemchuen, Somboon,Verpoort, Francis
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p. 882 - 887
(2017/03/13)
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- Substrate-Assisted, Transition-Metal-Free Diboration of Alkynamides with Mixed Diboron: Regio- and Stereoselective Access to trans-1,2-Vinyldiboronates
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A substrate-assisted diboration of alkynamides using the unsymmetrical pinacolato-1,8-diaminonaphthalenato diboron (pinBBdan) is described. The transition-metal-free reaction proceeds in a regio- and stereoselective fashion to exclusively afford trans-vinyldiboronates in good to excellent yields. Notably, Bdan and Bpin are installed on the α- and β-carbon atoms, respectively.
- Verma, Astha,Snead, Russell F.,Dai, Yumin,Slebodnick, Carla,Yang, Yinuo,Yu, Haizhu,Yao, Fu,Santos, Webster L.
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supporting information
p. 5111 - 5115
(2017/04/24)
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- Iron-catalyzed selective oxidation of α,β-unsaturated aldehydes to α,β-unsaturated carboxylic acids by molecular oxygen
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Selective oxidation of α,β-unsaturated aldehydes to α,β-unsaturated carboxylic acids was performed using O2 as the oxidant in the presence of a simple iron catalyst. The addition of an alkali metal carboxylate as a cocatalyst enhanced the selectivity for the desired product. Redox tuning of the iron catalyst via association with the alkali metal led to a controlled radical generation during the catalytic O2 oxidation.
- Tanaka, Shinji,Kon, Yoshihiro,Uesaka, Yumiko,Morioka, Ryo,Tamura, Masanori,Sato, Kazuhiko
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supporting information
p. 188 - 190
(2016/03/01)
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- Carboxylation of terminal alkynes with CO2 using novel silver N-heterocyclic carbene complexes
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Four novel N-heterocyclic carbene (NHC) silver complexes, I-IV, have been synthesized and characterized. The single X-ray crystal diffraction data indicate a dinuclear solid-state structure for I and III and a mononuclear structure for II and IV. These complexes have been successfully used as efficient catalysts for the C-H activating carboxylation of terminal alkynes with CO2. A wide range of substrates with various functional groups afforded the corresponding aryl or alkyl substituted propiolic acids in good yields under mild conditions. Moreover, the role of bases and the reaction mechanism is thoroughly discussed.
- Li, Shanshan,Sun, Jing,Zhang, Zhizhi,Xie, Ruixia,Fang, Xiangchen,Zhou, Mingdong
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p. 10577 - 10584
(2016/07/07)
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- A Strained Disilane-Promoted Carboxylation of Organic Halides with CO2 under Transition-Metal-Free Conditions
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By using a strained four-membered ring disilane (3,4-benzo-1,1,2,2-tetraethyldisilacyclobutene) and CsF, a wide range of aryl, alkenyl, alkynyl, benzyl, allyl, and alkyl halides was successfully carboxylated under an ambient CO2 atmosphere (CO2 balloon) at room temperature within 2 h. In this carboxylation, a highly reactive silyl anion, which is generated from the disilane and CsF, is a key to facilitating the formation of a carbanion equivalent. The resulting anionic species can be trapped with CO2 to produce carboxylic acids with high efficiency.
- Mita, Tsuyoshi,Suga, Kenta,Sato, Kaori,Sato, Yoshihiro
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supporting information
p. 5276 - 5279
(2015/11/18)
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- Palladium-catalyzed oxidative aminocarbonylation by decarboxylative coupling: Synthesis of alkynyl amides
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Alkynyl amides were synthesized from a palladium-catalyzed coupling reaction of alkynyl carboxylic acids and amines under carbon monoxide. The reaction was conducted with palladium(II) acetate (5 mol-%) and silver(I) oxide (1.0 equiv.) in acetonitrile at 80 °C for 1 h. This method provides good to moderate product yields and good functional group tolerance towards ketone, ester, and nitrile groups.
- Hwang, Jinil,Choi, Jinseop,Park, Kyungho,Kim, Wonyoung,Song, Kwang Ho,Lee, Sunwoo
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p. 2235 - 2243
(2015/04/14)
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- β-Ketophosphonate formation via aerobic oxyphosphorylation of alkynes or alkynyl carboxylic acids with H-phosphonates
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A synergistic Cu/Fe-catalyzed aerobic oxyphosphorylation of alkynes or alkynyl carboxylic acids with H-phosphonate is disclosed. The useful β-ketophosphonate products were obtained in good yields under oxygen atmosphere in a novel way. This reaction exhibits a wide substrate scope, and the mechanistic experiments indicate that a radical mechanism forms both C-P and C=O bonds simultaneously. This mechanism contrasts existing aerobic difunctionalization of alkynes.
- Zhou, Mingxin,Chen, Ming,Zhou, Yao,Yang, Kai,Su, Jihu,Du, Jiangfeng,Song, Qiuling
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supporting information
p. 1786 - 1789
(2015/04/14)
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- Carboxylic acids from primary alcohols and aldehydes by a pyridinium chlorochromate catalyzed oxidation
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A facile and quantitative preparation of carboxylic acids by a pyridinium chlorochromate (PCC) catalyzed (2 mol%) oxidation of primary alcohols and aldehydes using 2.2 equivalents and 1.1 equivalents of H5IO 6, respectively, in acetonitrile is described here. Georg Thieme Verlag Stuttgart.
- Hunsen, Mo
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p. 2487 - 2490
(2007/10/03)
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- TMS Triflate-Catalyzed Cleavage of Prenyl (3-Methylbut-2-enyl) Ester
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(Matrix Presented) Prenyl (3-methylbut-2-enyl) ester is catalytically cleaved by TMS triflate affording carboxylic acid and isoprene in high yield under mild conditions with high chemoselectivity without causing epimerization of the neighboring chiral cen
- Nishizawa, Mugio,Yamamoto, Hirofumi,Seo, Ken,Imagawa, Hiroshi,Sugihara, Takumichi
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p. 1947 - 1949
(2007/10/03)
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- Oxygenation of alkynes to α,β-acetylenic ketones with dioxygen catalyzed by N-hydroxyphthalimide combined with a transition metal
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Alkynes were successfully converted into α,β-acetylenic carbonyl compounds through radical-catalyzed aerobic oxidation using N-hydroxyphthalimide (NHPI) combined with a transion metal under mild conditions.
- Sakaguchi, Satoshi,Takase, Tomoyuki,Iwahama, Takahiro,Ishii, Yasutaka
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p. 2037 - 2038
(2007/10/03)
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- Synthesis of [1-11C]-2-octynoic acid, [1-11C]-2-decynoic acid and [1-11C]-3-(R,S)-methylocatanoic acid as potential markers for PET studies of fatty acid metabolism
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[1-11C]-2-Octynoic acid, [1-11C]-2-decynoic acid and [1-11C]-3-(R,S)-methyloctanoic acid have been synthesized in order to evaluate these compounds as PET (Positron Emission Tomography) tracers for imaging in vivo medium-chain acyl-CoA dehydrogenase and medium-chain fatty acid utilization. The synthesis was performed by the Grignard reaction between alkylmagnesium bromides and [11C]CO2. The radiochemical yields of [1-11C]-2-octynoic acid, [1-11C]-2-decynoic acid, and [1-11C]-3-(R,S)-methyloctanoic acid were 10, 7 and 1% based on the [11C]CO2 used respectively. Radiochemical purity was >99% in all cases.
- Kawashima, Hidefumi,Yajima, Kazuyoshi,Kuge, Yuji,Hashimoto, Naoto,Miyake, Yoshihiro
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p. 181 - 193
(2007/10/03)
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- Synthesis of 2-acetylenic carboxylic acids, 1-sulfinyl and 1-sulfonyl- 2-ketones from 2-acetylenic phenyl sulfides
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Monochlorination at the 1-position with sulfuryl chloride, followed by methanolysis converted 2-acetylenic phenyl sulfides into 1-methoxy-2- acetylenic phenyl sulfides. Oxidation with chromic acid gave 2-acetylenic carboxylic acids. Oxidation of 2-acetylenic phenyl sulfides with Oxone and hydrogen peroxide in acetic acid gave the corresponding sulfoxides and sulfones respectively. Diethylamine addition to the triple bond produced enamines which were hydrolyzed with aqueous hydrochloric acid to the corresponding 1-sulfinyl and 1-sulfonyl-2-ketones.
- Fortes, Carlos C.,Garrote, Clevia F.D.
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p. 2993 - 3026
(2007/10/03)
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- Conversion of Allyl Alk-2-ynoates to Alk-2-ynoic Acids Using Morpholine and Palladium(0)-Bis(diphenylphosphino)alkane Catalyst; Synthesis of 2,2,3,3-Tetradehydro PGE1
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Allyl alk-2-ynoates can be readily converted into alk-2-ynoic acids by the reaction with morpholine in the presence of a palladium-diphenylphosphinopropane catalyst, thus providing the chemical deprotection method of allyl ester of 2,2,3,3-tetradehydro PGE1.
- Okamoto, Sentaro,Ono, Naoya,Tani, Kousuke,Yoshida, Yukio,Sato, Fumie
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p. 279 - 280
(2007/10/02)
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- (Ethoxycarbonyliodomethyl)triphenylphosphonium Iodide: A Convenient Reagent for the Direct Synthesis of β-Substituted Propiolic Acids via the Corresponding Esters
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Reaction between (ethoxycarbonyliodomethyl)triphenylphosphonium iodide, potassium carbonate, and various aromatic or aliphatic aldehydes in a liquid solid two phases system gives β-substituted propiolic esters.The corresponding acids are obtained in good yield by hydrolysis.
- Chenault, Jaques,Dupin, Jean-Francois E.
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p. 498 - 499
(2007/10/02)
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- Chain-extension Reactions of Acetylenes. Part 4. Reaction of 1,3-Dilithioacetylides with Carbonyl Electrophiles, Hexamethylphosphoric Triamide, and Benzylideneaniline
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The regioselectivity of the reactions of 1,3-dilithioalk-1-ynes with various electrophiles has been examined.With formaldehyde and cyclic ketones, reaction occur at C-1 and C-3 to give alk-2-yne-1,5-diols.In contrast reactions with carbon dioxide give allene-1,3-dicarboxylic acids. 1,3-Dilithioalk-1-ynes decompose hexamethylphosphoric triamide and the resulting N-methylmethyleneamine undergoes addition only at the propargylic site.Further reaction with either 1-bromobutane or water gives alkynylamines.Benzylideneaniline also reacts with 1,3-dilithiohex- and hept-1-ynes only at the propargylic site to give N-phenylbut-3-ynylamines.
- Pover, Keith A.,Scheinmann, Feodor
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p. 2338 - 2345
(2007/10/02)
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