- Iodonium Cation-Pool Electrolysis for the Three-Component Synthesis of 1,3-Oxazoles
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The synthesis of 1,3-oxazoles from symmetrical and unsymmetrical alkynes was realized by an iodonium cation-pool electrolysis of I2 in acetonitrile with a well-defined water content. Mechanistic investigations suggest that the alkyne reacts with the acetonitrile-stabilized I+ ions, followed by a Ritter-type reaction of the solvent to a nitrilium ion, which is then attacked by water. The ring closure to the 1,3-oxazoles released molecular iodine, which was visible by the naked eye. Also, some unsymmetrical internal alkynes were tested and a regioselective formation of a single isomer was determined by two-dimensional NMR experiments.
- Sattler, Lars E.,Hilt, Gerhard
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p. 605 - 608
(2020/12/07)
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- Synthesis and Photochemical Application of Hydrofluoroolefin (HFO) Based Fluoroalkyl Building Block
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A novel fluoroalkyl iodide was synthesized on multigram scale from refrigerant gas HFO-1234yf as cheap industrial starting material in a simple, solvent-free, and easily scalable process. We demonstrated its applicability in a metal-free photocatalytic ATRA reaction to synthesize valuable fluoroalkylated vinyl iodides and proved the straightforward transformability of the products in cross-coupling chemistry to obtain conjugated systems.
- Varga, Bálint,Tóth, Balázs L.,Béke, Ferenc,Csenki, János T.,Kotschy, András,Novák, Zoltán
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p. 4925 - 4929
(2021/07/01)
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- Decarboxylation-triggered homo-Nazarov cyclization of cyclic enol carbonates catalyzed by rhenium complex
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Decarboxylative homo-Nazarov cyclization catalyzed by a Lewis acid was achieved using a cyclic enol carbonate bearing a cyclopropane moiety as a substrate. Various substrates were converted into the corresponding multi-substituted cyclohexenones in good yieldsviadecarboxylation, followed by 6-membered ring formation involving cyclopropane-ring-opening.
- Kimaru, Natsuki,Komatsuki, Keiichi,Saito, Kodai,Yamada, Tohru
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p. 6133 - 6136
(2021/06/30)
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- Synthesis of alkynes under dry reaction conditions
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An easy synthetic method was developed under dry reaction conditions for the preparation of terminal alkynes from 1,1-dibromoalkenes and in the presence of succinimide which acts as a nucleophile and proton donor. It was demonstrated with the synthesis of a broad spectrum of terminal alkynes and extended to synthesize internal alkynes under tandem reaction conditions.
- Rao, Maddali L.N.,Shamim Islam, Sk
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supporting information
(2021/04/19)
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- BIPHENYL COMPOUNDS AS SOCE MODULATORS, COMPOSITIONS AND USES THEREOF
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Compound of formula (I) able to modulate Store Operated Calcium Entry (SOCE). The disclosure also relates to compositions and uses of compounds of formula (I) for treatment of disease condition depending on increased/ decreased activity of SOCE.
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Page/Page column 30; 34
(2021/08/27)
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- Synthesis, in-situ membrane preparation, and good gas permselectivity of insoluble poly(substituted acetylene)s loosely cross-linked with short and soft siloxane and silanol linkages
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Insoluble but membrane-formable poly(substituted acetylene)s loosely cross-linked by short and soft Si–O–Si and SiOH---(OH)Si linkages have been synthesized from the corresponding monomers having one or two SiOH groups. These monomers have been polymerized in homogeneous systems to produce homogeneous polymer solutions in toluene. The resulting solutions were cast on polytetrafuluoroethylene sheets followed by evaporation of the solvent to give tough and flexible membranes which were completely insoluble. The membranes showed good oxygen and carbon oxide permselectivity and their plots in PO2 vs PO2/PN2 graph exceeded the 1991 Robeson's upper bound and very close to the 2008 Robeson's upper bound. The excellent selectivity are caused by enhancement of diffusion selectivity by the soft network structure which can create small pores (i.e., ultramicro pores) based on the short linkages. No drop in permeability may be due to the soft Si–O–Si and SiOH---(OH)Si linkages. In addition no change in PO2 and PO2/PN2 by aging was observed.
- Wang, Jianjun,Aoki, Toshiki,Kaneko, Takashi,Teraguchi, Masahiro
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- Self-Assembly and Molecular Recognition in Water: Tubular Stacking and Guest-Templated Discrete Assembly of Water-Soluble, Shape-Persistent Macrocycles
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Supramolecular chemistry in aqueous media is an area with great fundamental and practical significance. To examine the role of multiple noncovalent interactions in controlled assembling and binding behavior in water, the self-association of five water-soluble hexakis(m-phenylene ethynylene) (m-PE) macrocycles, along with the molecular recognition behavior of the resultant assemblies, is investigated with UV-vis, fluorescence, CD, and NMR spectroscopy, mass spectrometry, and computational studies. In contrast to their different extents of self-aggregation in organic solvents, all five macrocycles remain aggregated in water at concentrations down to the micromolar (μM) range. CD spectroscopy reveals that 1-F6 and 1-H6, two macrocycles carrying chiral side chains and capable of H-bonded self-association, assemble into tubular stacks. The tubular stacks serve as supramolecular hosts in water, as exemplified by the interaction of macrocycles 1-H6 and 2-H6 and guests G1 through G4, each having a rod-like oligo(p-phenylene ethynylene) (p-PE) segment flanked by two hydrophilic chains. Fluorescence and 1H NMR spectroscopy revealed the formation of kinetically stable, discrete assemblies upon mixing 2-H6 and a guest. The binding stoichiometry, determined with fluorescence, 1H NMR, and ESI-MS, reveals that the discrete assemblies are novel pseudorotaxanes, each containing a pair of identical guest molecules encased by a tubular stack. The two guest molecules define the number of macrocyclic molecules that comprise the host, which curbs the "infinite" stack growth, resulting in a tubular stack with a cylindrical pore tailoring the length of the p-PE segment of the bound guests. Each complex is stabilized by the action of multiple noncovalent forces including aromatic stacking, side-chain H-bonding, and van der Waals interactions. Thus, the interplay of multiple noncovalent forces aligns the molecules of macrocycles 1 and 2 into tubular stacks with cylindrical inner pores that, upon binding rod-like guests, lead to tight, discrete, and well-ordered tubular assemblies that are unprecedented in water.
- Wang, Qiuhua,Zhong, Yulong,Miller, Daniel P.,Lu, Xiaoxing,Tang, Quan,Lu, Zhong-Lin,Zurek, Eva,Liu, Rui,Gong, Bing
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p. 2915 - 2924
(2020/02/04)
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- Thermal decarboxylative Nazarov cyclization of cyclic enol carbonates involving chirality transfer
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Decarboxylative Nazarov cyclization of chiral cyclic enol carbonates proceeded to afford chiral 2-cyclopentenones with excellent chirality transfer under thermal conditions without any catalyst. Interestingly, the thermal decarboxylative Nazarov cyclization furnished the desired product with better chirality transfer than the Lewis acid-catalyzed reaction.
- Kozuma, Akane,Komatsuki, Keiichi,Saito, Kodai,Yamada, Tohru
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- Copper-catalyzed (4+1) and (3+2) cyclizations of iodonium ylides with alkynes
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The copper(ii)-catalyzed (4+1) cyclizations and copper(i)-catalyzed (3+2) cycloadditions of iodonium ylides and alkynes were successfully developed by employing efficient and safe iodonium ylides instead of traditional diazo compounds. Highly functionaliz
- Liang, Hao,He, Xiaobo,Zhang, Yaqi,Chen, Bin,Ouyang, Jia-Sheng,Li, Yongsu,Pan, Bendu,Subba Reddy, Chitreddy V.,Chan, Wesley Ting Kwok,Qiu, Liqin
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p. 11429 - 11432
(2020/10/12)
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- Fe-Catalyzed Selective Cyclopropanation of Enynes under Photochemical or Thermal Conditions
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The nucleophilic Fe-complex Bu4N[Fe(CO)3(NO)] (TBA[Fe]) catalyzes the cyclopropanation of enynes to substituted propargyl cyclopropanes using diazoesters as carbene surrogates. The catalyst can be activated either thermally in the presence of catalytic amounts of 4-nitroanisole or under photochemical conditions. Cyclopropanation occurs selectively at the enyne moiety; alternative olefinic moieties remain intact.
- Picher, Marie-Idrissa,Plietker, Bernd
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supporting information
p. 340 - 344
(2020/01/11)
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- In Situ Generation of Alkynylzinc and Its Subsequent Negishi Reaction in a Flow Reactor
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A highly efficient and convenient Negishi cross-coupling reaction has been developed for the synthesis of unsymmetrical alkynes and enynes in a continuous-flow process. The reaction proceeds through an in situ generated alkynylzinc reagent by the reaction of lithium acetylide with zinc halide at room temperature followed by a cross-coupling reaction with aryl or vinyl iodides. The notable features of this work compared to the conventional benchtop method are mild reaction conditions, good to excellent yields, broad functional-group compatibility, short residence time (73 sec) and especially desilylation of TMS group with the residence time of only 10.5 sec.
- Kandasamy, Mohanraj,Huang, Yu- Hsuan,Ganesan, Balaji,Senadi, Gopal Chandru,Lin, Wei-Yu
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p. 4349 - 4356
(2019/07/03)
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- DBU-Mediated Synthesis of Aryl Acetylenes or 1-Bromoethynylarenes from Aldehydes
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Two well known synthetic organic reactions Ramirez olefination and Corey-fuchs reactions are integrated in one-pot sequential manner for the synthesis of arylacetylenes and 1,3-enynes starting directly from commercially available aldehydes. The bicyclic amidine 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) along with additive NaOH not only exclusively afforded the terminal alkynes directly from the aldehydes, but also enhanced the reaction rate. The dynamic nature of DBU also facilitated the isolation of 1-bromoalkynes intermediate products. Selection of additive from NaOH and H2O served as a switch for the synthesis of terminal alkyne and 1-bromoalkynes, respectively. (Figure presented.).
- Thummala, Yadagiri,Karunakar, Galla V.,Doddi, Venkata Ramana
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supporting information
p. 611 - 616
(2019/01/04)
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- Regioselective Gold-Catalyzed Hydration of CF3- and SF5-alkynes
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The regioselective gold-catalyzed hydration of CF3- and SF5-alkynes is described. The corresponding trifluoromethylated and pentasulfanylated ketones are obtained in up to 91% yield as single regioisomers showcasing the use of CF3 and SF5 as highly efficient directing groups in this reaction. Notably, this transformation represents the first use of CF3- and SF5-alkynes in gold catalysis.
- Cloutier, Mélissa,Roudias, Majdouline,Paquin, Jean-Fran?ois
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supporting information
p. 3866 - 3870
(2019/05/24)
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- BF3·OEt2-Promoted Propargyl Alcohol Rearrangement/[1,5]-Hydride Transfer/Cyclization Cascade Affording Tetrahydroquinolines
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An efficient BF3·OEt2-mediated propargyl alcohol rearrangement/[1,5]-hydride transfer/cyclization cascade for the synthesis of tetrahydroquinoline derivatives has been described. The substituents adjacent to triple bonds play an important role in the formation of ketones (via [1,3]-hydroxyl shift) or alkenyl fluorides which are products of formal trans-carbofluorination of internal alkynes. This method provides a rapid access to diverse heterocycles in moderate to excellent yields.
- Zhao, Shuang,Wang, Xiaoyang,Wang, Pengfei,Wang, Guangwei,Zhao, Wentao,Tang, Xiangyang,Guo, Minjie
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supporting information
p. 3990 - 3993
(2019/06/14)
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- Bis(het)aryl-1,2,3-triazole quinuclidines as α7 nicotinic acetylcholine receptor ligands: Synthesis, structure affinity relationships, agonism activity, [18F]-radiolabeling and PET study in rats
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In this paper we describe the design and synthesis of bis(Het)Aryl-1,2,3-triazole quinuclidine α7R ligands using an efficient three-step sequence including a Suzuki-Miyaura cross coupling reaction with commercially available and home-made boron derivatives. The exploration of SAR required the preparation of uncommon boron derivatives. Forty final drugs were tested for their ability to bind the target and nine of them exhibited Ki values below nanomolar concentrations. The best scores were always obtained when the 5-phenyl-2-thiophenyl core was attached to the triazole. The selectivity of these compounds towards the nicotinic α4β2 and serotoninergic 5HT3 receptors was assessed and their brain penetration was quantified by the preparation and in vivo evaluation of two [18F] radiolabelled derivatives. It can be expected from our results that some of these compounds will be suitable for further developments and will have effects on cognitive disorders.
- Ouach, Aziz,Vercouillie, Johnny,Bertrand, Emilie,Rodrigues, Nuno,Pin, Frederic,Serriere, Sophie,Boiaryna, Liliana,Chartier, Agnes,Percina, Nathalie,Tangpong, Pakorn,Gulhan, Zuhal,Mothes, Celine,Deloye, Jean-Bernard,Guilloteau, Denis,Page, Guylene,Suzenet, Franck,Buron, Frederic,Chalon, Sylvie,Routier, Sylvain
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p. 449 - 469
(2019/07/03)
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- Au-Catalyzed Intermolecular [2+2] Cycloadditions between Chloroalkynes and Unactivated Alkenes
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The [2+2] cycloaddition is a versatile strategy for the synthesis of strained cyclobutenes of high synthetic value. In this study, two efficient intermolecular [2+2] cycloadditions between two different types of chloroalkynes and unactivated alkene are realized with gold catalysis. Of significance is that the reaction works with challenging monosubstituted unactivated alkenes, which is unprecedented in gold catalysis and scarcely documented in other metal-catalyzed/promoted reactions; moreover, the reaction exhibits excellent regioselectivities, which are much better than those reported in literature. With 1,2-disubstituted unactivated alkenes, the reaction is largely stereospecific. The cyclobutene products can be prepared in nearly gram scale and readily undergo further reactions including various cross-coupling reactions using the C(sp2)-Cl and/or C(sp2)-SPh bond, which in turn substantially broaden the scope of accessible cyclobutenes and enhance the synthetic utility of this bimolecular reaction.
- Bai, Yu-Bin,Luo, Zaigang,Wang, Yuguang,Gao, Jin-Ming,Zhang, Liming
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p. 5860 - 5865
(2018/05/14)
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- COMPOUND FOR ORGANIC OPTOELECTRONIC DEVICE, ORGANIC OPTOELECTRONIC DEVICE AND DISPLAY APPARATUS
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The present invention relates to a compound for an organic optoelectronic device represented by chemical formula 1, an organic optoelectronic device employing the same and a display device apparatus. The details of chemical formula 1 are as defined in the specification.
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- An Additive-Free, Base-Catalyzed Protodesilylation of Organosilanes
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We report an additive-free, base-catalyzed C-, N-, O-, and S-Si bond cleavage of various organosilanes in mild conditions. The novel catalyst system exhibits high efficiency and good functional group compatibility, providing the corresponding products in good to excellent yields with low catalyst loadings. Overall, this transition-metal-free process may offer a convenient and general alternative to current employing excess bases, strong acids, or metal-catalyzed systems for the protodesilylation of organosilanes.
- Yao, Wubing,Li, Rongrong,Jiang, Huajiang,Han, Deman
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p. 2250 - 2255
(2018/02/23)
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- SO2F2-Mediated Oxidative Dehydrogenation and Dehydration of Alcohols to Alkynes
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Direct synthesis of alkynes from inexpensive, abundant alcohols was achieved in high yields (greater than 40 examples, up to 95% yield) through a SO2F2-promoted dehydration and dehydrogenation process. This straightforward transformation of sp3-sp3 (C-C) bonds to sp-sp (C=C) bonds requires only inexpensive and readily available reagents (no transition metals) under mild conditions. The crude alkynes are sufficiently free of impurities to permit direct use in further transformations, as illustrated by regioselective Huisgen alkyne-azide cycloaddition reactions with PhN3 to give 1,4-substituted 1,2,3-traiazoles (16 examples, up to 92% yield) and Sonogashira couplings (10 examples, up to 77% yield).
- Zha, Gao-Feng,Fang, Wan-Yin,Li, You-Gui,Leng, Jing,Chen, Xing,Qin, Hua-Li
-
supporting information
p. 17666 - 17673
(2019/01/04)
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- Metal-free synthesis of imidazole by BF3·Et2O promoted denitrogenative transannulation of N-sulfonyl-1,2,3-triazole
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BF3·Et2O promoted metal-free denitrogenative transannulation of N-sulfonyl-1,2,3-triazole was reported. Rather than transition metals, BF3·Et2O was employed for the first time to promote the formation of α-diazoimines from N-sulfonyl-1,2,3-triazoles in nitriles, leading to the synthesis of various imidazoles. The protocol tolerates a broad range of functional groups and could also be applied to the late-stage modification of bioactive molecules, demonstrating the potential of this protocol in organic synthesis. A plausible mechanism was proposed.
- Yang, Dongdong,Shan, Lihong,Xu, Ze-Feng,Li, Chuan-Ying
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p. 1461 - 1464
(2018/03/08)
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- Borazino-Doped Polyphenylenes
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The divergent synthesis of two series of borazino-doped polyphenylenes, in which one or more aryl units are replaced by borazine rings, is reported for the first time, taking advantage of the decarbonylative [4 + 2] Diels-Alder cycloaddition reaction between ethynyl and tetraphenylcyclopentadienone derivatives. Because of the possibility of functionalizing the borazine core with different groups on the aryl substituents at the N and B atoms of the borazino core, we have prepared borazino-doped polyphenylenes featuring different doping dosages and orientations. To achieve this, two molecular modules were prepared: a core and a branching unit. Depending on the chemical natures of the central aromatic module and the reactive group, each covalent combination of the modules yields one exclusive doping pattern. By means of this approach, three- and hexa-branched hybrid polyphenylenes featuring controlled orientations and dosages of the doping B3N3 rings have been prepared. Detailed photophysical investigations showed that as the doping dosage is increased, the strong luminescent signal is progressively reduced. This suggests that the presence of the B3N3 rings engages additional deactivation pathways, possibly involving excited states with an increasing charge-separated character that are restricted in the full-carbon analogues. Notably, a strong effect of the orientational doping on the fluorescence quantum yield was observed for those hybrid polyphenylene structures featuring low doping dosages. Finally, we showed that Cu-catalyzed 1,3-dipolar cycloaddition is also chemically compatible with the BN core, further endorsing the inorganic benzene as a versatile aromatic scaffold for engineering of molecular materials with tailored and exploitable optoelectronic properties.
- Marinelli, Davide,Fasano, Francesco,Najjari, Btissam,Demitri, Nicola,Bonifazi, Davide
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p. 5503 - 5519
(2017/04/27)
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- Enantioselective synthesis of β-fluoro-β-aryl-α-aminopentenamides by organocatalytic [2,3]-sigmatropic rearrangement
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The tetramisole-promoted catalytic enantioselective [2,3]-sigmatropic rearrangement of quaternary ammonium salts bearing a (Z)-3-fluoro-3-arylprop-2-ene group generates, after addition of benzylamine, a range of β-fluoro-β-aryl-α-aminopentenamides containing a stereogenic tertiary fluorine substituent. Cyclic and acyclic nitrogen substituents as well as various aromatic substituents are tolerated, giving the β-fluoro-β-aryl-α-aminopentenamide products in up to 76% yield, 96:4 dr, and 98:2 er.
- Kasten, Kevin,Slawin, Alexandra M. Z.,Smith, Andrew D.
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p. 5182 - 5185
(2017/11/06)
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- Heme Protein Catalysts for Carbon-Silicon Bond Formation In Vitro and In Vivo
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The present invention provides compositions and methods for catalyzing the formation of carbon-silicon bonds using heme proteins. In certain aspects, the present invention provides heme proteins, including variants and fragments thereof, that are capable of carrying out in vitro and in vivo carbene insertion reactions for the formation of carbon-silicon bonds. In other aspects, the present invention provides methods for producing an organosilicon product, the method comprising providing a silicon-containing reagent, a carbene precursor, and a heme protein; and combining the components under conditions sufficient to produce an organosilicon product. Host cells expressing the heme proteins are also provided by the present invention.
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Paragraph 0268
(2017/08/26)
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- Photochemical Dual-Catalytic Synthesis of Alkynyl Sulfides
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A photochemical dual-catalytic cross-coupling to form alkynyl sulfides via C(sp)?S bond formation is described. The cross-coupling of thiols and bromoalkynes is promoted by a soluble organic carbazole-based photocatalyst using continuous flow techniques. Synthesis of alkynyl sulfides bearing a wide range of electronically and sterically diverse aromatic alkynes and thiols can be achieved in good to excellent yields (50–96 %). The simple continuous flow setup also allows for short reaction times (30 min) and high reproducibility on gram scale. In addition, we report the first application of photoredox/nickel dual catalysis towards macrocyclization, as well as the first example of the incorporation of an alkynyl sulfide functional group into a macrocyclic scaffold.
- Santandrea, Jeffrey,Minozzi, Clémentine,Cruché, Corentin,Collins, Shawn K.
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supporting information
p. 12255 - 12259
(2017/09/06)
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- Palladium-catalyzed tandem C-H functionalization/cyclization strategy for the synthesis of 5-hydroxybenzofuran derivatives
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A palladium-catalyzed benzoquinone C-H functionalization/ cyclization strategy with terminal alkynes was employed for the synthesis of some biologically relevant 2, 3-disubstituted 5-hydroxybenzofuran derivatives. The benzoquinone acts as a reactant as well as an oxidant. During the process, an additional alkyne functionality can be introduced at the C3 position of the benzofuran. Base, ligand, and external oxidant are not required in this protocol.
- Ichake, Sachin S.,Konala, Ashok,Kavala, Veerababurao,Kuo, Chun-Wei,Yao, Ching-Fa
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supporting information
p. 54 - 57
(2017/11/28)
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- Na2S-mediated synthesis of terminal alkynes from: Gem -dibromoalkenes
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The Na2S-mediated facile synthesis of terminal alkynes from gem-dibromoalkenes, at 20/40 °C under open flask conditions has been developed. Various precursors derived from heteroaromatic/aromatic/aliphatic aldehydes were found compatible. The reaction is proposed to proceed through the Fritsch-Buttenberg-Wiechell (FBW) rearrangement involving the corresponding vinyl carbene. Using mild reaction conditions with inexpensive Na2S·9H2O under air atmosphere has significant advantages over earlier routes.
- Singh, Radhey M.,Nandini, Durgesh,Bharadwaj, Kishor Chandra,Gupta, Tanu,Singh, Raj Pal
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p. 9979 - 9982
(2017/12/26)
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- COMPOUNDS HAVING NEGATIVE OPTICAL DISPERSION, NEGATIVE OPTICAL DISPERSION COMPOSITION COMPRISING THE COMPOUNDS, AND OPTICALLY ANISOTROPIC BODY COMPRISING THE COMPOSITION
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The present invention relates to a reverse dispersive compound, a reverse dispersive composition and an optical anisotropic body comprising the same. The reverse dispersive compound of the present invention is represented by chemical formula 1, and has improved orientation, thereby enabling to provide an optical anisotropic body having excellent optical properties.COPYRIGHT KIPO 2016
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- A copper (II) (II) composite chlorinating agent and copper-based composite chlorinating agent synthesis of 1-chloro-2-aryl acetylene method
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The invention discloses a copper (II) composite chlorinating agent and a method for synthesizing 1-chlorine-2-aryl acetylene based on the copper (II) composite chlorinating agent. The structural formula of the copper (II) composite chlorinating agent is CuCl2.xNaCl.yAl2O3. The chlorinating agent is applicable to chlorination of various substituted aryl acetylene substrates, and is high in universality; the chlorinating agent can directly carry out chlorination reaction on aryl acetylene so as to obtain a 1-chlorine-2-aryl acetylene product; the method is mild in reaction condition, 1-chlorine-2-aryl acetylene can be synthesized with high yield and high selectivity, and the production cost of the 1-chlorine-2-aryl acetylene derivative is greatly lowered.
- -
-
Paragraph 0090-0092
(2016/11/24)
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- Synthesis of 1-arylsulfonyl-1,2,3-triazoles from (Z)-arylvinyl bromides by sequential elimination–cycloaddition reaction
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[Figure not available: see fulltext.]Efficient synthesis of 1-arylsulfonyl-1,2,3-triazoles from easily available (Z)-arylvinyl bromides is described. The sequential reaction involves elimination of HBr from (Z)-arylvinyl bromides promoted by KOH and copper-catalyzed (3+2) cycloaddition reaction between the alkyne intermediates and sulfonyl azides.
- Zhang, Wensheng,Xu, Wenjing
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p. 192 - 195
(2016/07/28)
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- Synthesis of 1,2-biphenylethane based single-molecule diodes
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We have described the synthesis of novel biphenylethane-based wires for molecular electronics. Exceptional single-molecule diode behavior was predicted for unsymmetrically substituted biphenylethane derivatives, synthesized here using the so far unexplored unsymmetrically substituted 1,2-bis(4-bromophenyl)ethanes as key intermediates, which were obtained from the corresponding tolane precursor by selective hydrogenation.
- Galán, Elena,Perrin, Mickael L.,Lutz, Martin,Van Der Zant, Herre S. J.,Grozema, Ferdinand C.,Eelkema, Rienk
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p. 2439 - 2443
(2016/03/01)
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- Cleavage of the Carbon–Carbon Triple Bonds of Arylacetylenes for the Synthesis of Arylnitriles without a Metal Catalyst
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Cleavage of the carbon–carbon triple bonds of alkynes was achieved, which led to the synthesis of arylnitriles under transition-metal-free conditions. A vast range of terminal alkyne substrates underwent this reaction to provide the corresponding nitriles in moderate to good yields with good functional group tolerance.
- Lin, Yuanguang,Song, Qiuling
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supporting information
p. 3056 - 3059
(2016/07/12)
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- Efficient synthesis of N-arylsulfonyl-1,2,3-triazoles from 1,1-dibromo-2-arylethylenes
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N-arylsulfonyl-1,2,3-triazoles were synthesized from 1,1-dibromo-2-arylethylenes via a one-pot reaction involving the Cs2CO3-mediated dehydrobromination process of the dibromoalkenes to produce alkynes followed by the Cu(I)-catalyzed Huisgen cycloaddition of the alkyne intermediates with tosyl azide.
- Xu, Wenjing,Zhang, Wensheng,Zhang, Fei
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p. 165 - 167
(2016/07/06)
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- Rh(III)-catalyzed cyclization reaction of azoles with alkynes: Efficient synthesis of azole-fused-pyridines
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A Rh(III)-catalyzed cyclization of azoles with alkynes has been developed. A variety of azole-fused-pyridines were obtained in good to excellent yields and regioselectivity. Both the C5 and the C4 position of azoles were suitable for the reaction.
- Chen, Xuebing,Wu, Youzhi,Xu, Jinyi,Yao, Hequan,Lin, Aijun,Huang, Yue
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p. 9186 - 9189
(2015/09/07)
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- The Dual Role of 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) in the Synthesis of Terminal Aryl- and Styryl-Acetylenes via Umpolung Reactivity
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The dual role of the bicyclic amidine base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was demonstrated in a synthesis of terminal aryl- and styryl-acetylenes. Mechanistically, a tandem process involving elimination/Umpolung/protonation occurs in a single step to generate terminal aryl- and styryl-acetylenes from geminal dibromoalkenes. The key to the success of this transformation lies in the organobase-mediated generation of the acetylide from the 1-bromoalkynes at room temperature. The unique characteristics of DBU as an inherently safer reagent make it an attractive alternative to previous systems wherein required pyrophoric reagents and nonambient temperatures remain unsolved issues. The procedure does not work for the synthesis of alkyl-acetylenes.
- Morri, Ashok Kumar,Thummala, Yadagiri,Doddi, Venkata Ramana
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p. 4640 - 4643
(2015/09/28)
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- Tandem Claisen Rearrangement/6-endo Cyclization Approach to Allylated and Prenylated Chromones
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Allyl, dimethylallyl and prenyl ethers derived from o-acylphenols reacted upon microwave irradiation to form C-allylated or -prenylated chromone derivatives, depending on the substitution pattern of the arene and the allyl substituent. The reaction proceeds through a tandem Claisen rearrangement and 6-endo-trig or 6-endo-dig cyclization sequence. For prenyl ethers, the tandem sequence can be extended by a Cope rearrangement to furnish 6-prenylchromones. The method is potentially useful for the synthesis of natural products and drugs.
- Schmidt, Bernd,Riemer, Martin,Schilde, Uwe
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supporting information
p. 7602 - 7611
(2016/01/25)
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- An efficient method for the production of terminal alkynes from 1,1-dibromo-1-alkenes and its application in the total synthesis of natural product dihydroxerulin
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An efficient method of preparing various terminal alkynes from 1,1-dibromo-1-alkenes by using TBAF (tetra-n-butylammonium fluoride) as a base and triphenylphosphane as a reductant was developed. This method is strong base and low/high temperatures free, and can tolerate a broad range of substrates. These advantages were well demonstrated by the application of this method to the total synthesis of polyene natural product dihydroxerulin.
- Liu, Shihui,Chen, Xiaobei,Hu, Yanwei,Yuan, Laiqi,Chen, Shaohua,Wu, Ping,Wang, Wei,Zhang, Shilei,Zhang, Wei
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p. 553 - 560
(2015/03/05)
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- CO extrusion in homogeneous gold catalysis: Reactivity of gold acyl species generated through water addition to gold vinylidenes
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Herein, we describe a new gold-catalyzed decarbonylative indene synthesis. Synergistic σ,π-activation of diyne substrates leads to gold vinylidene intermediates, which upon addition of water are transformed into gold acyl species, a type of organogold compound hitherto only scarcely reported. The latter are shown to undergo extrusion of CO, an elementary step completely unknown for homogeneous gold catalysis. By tuning the electronic and steric properties of the starting diyne systems, this new reactivity could be exploited for the synthesis of indene derivatives in high yields.
- Bucher, Janina,St?sser, Tim,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
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supporting information
p. 1666 - 1670
(2015/01/30)
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- New hole transporting materials based on hexaarylbenzene and aromatic amine moiety for organic light-emitting diodes
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Three different new hole transport compounds, namely DPAP-TB, 1-PNAP-TB and 2-PNAP-TB, were synthesized by Sonogashira coupling and Diels-Alder reaction. Synthesized materials exhibited high Tgin the range of 118 to 133 °C. These values are higher than that of NPB, which is commonly used as a hole transporting material. OLED devices were fabricated by the synthesized compounds using the solution process as a hole transporting layer. Device structure was ITO/PEDOT:PSS (40 nm)/synthesized compounds or NPB (20 nm)/Alq3 (70 nm)/LiF/Al. Luminance efficiencies and external quantum efficiencies of DPAP-TB, 1-PNAP-TB and 2-PNAP-TB devices were 3.98, 4.62, 4.22 cd/A, and 1.35, 1.56, 1.43% at 20 mA/cm2, respectively. In luminance efficiency and external quantum efficiency, 1-PNAP-TB especially had superior property to NPB. Copyright
- Kim, Seungho,Lee, Sang-Ho,Shin, Hwangyu,Kay, Kwang-Yol,Park, Jongwook
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p. 6382 - 6385
(2014/11/07)
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- 2-(1,2,3-Triazol-4-yl)pyridine-containing ethynylarenes as selective 'turn-on' fluorescent chemosensors for Ni(II)
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A series of ethynylarene compounds containing 2-(1,2,3-triazol-4-yl)pyridine chelating units were studied as fluorescent chemosensors for metal cations in aqueous solution. Analogs possessing two chelating units bridged by either 1,4-diethynylphenyl or 2,7-diethynylnaphthyl subunits displayed large hypsochromic shifts coupled with signal intensification when exposed to increasing concentrations of Ni(II), a unique response among 22 metal cation analytes. This response was shown to be reversible, and is proposed to derive from disruption of aggregate formation upon Ni(II) binding at the peripheral chelating units.
- Christensen, Joseph A.,Fletcher, James T.
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p. 4612 - 4615
(2014/12/10)
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- Autotandem catalysis: Synthesis of pyrroles by gold-catalyzed cascade reaction
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A novel synthesis of substituted pyrroles by a gold(I)-catalyzed cascade reaction has been developed. The reaction proceeded with an autotandem catalysis consisting of an initial addition of gold-acetylide to an acetal moiety and was followed by gold-catalyzed 5-endo-dig cyclization and aromatization. Gold catalysts play a dual role in activating nucleophilicity or electrophilicity of terminal acetylenes by forming gold-acetylides or by π-coordination. The formal (3 + 2) annulation of two components provided a variety of substituted pyrroles in a modular fashion.
- Ueda, Hirofumi,Yamaguchi, Minami,Kameya, Hiroshi,Sugimoto, Kenji,Tokuyama, Hidetoshi
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p. 4948 - 4951
(2015/04/27)
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- Aerobic oxynitration of alkynes with tBuONO and TEMPO
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An efficient method for stereoselective nitroaminoxylation of alkyne has been reported. The reaction enjoys a broad substrate scope, good functional group tolerance, and high yields. Synthetically useful α-nitroketones can be accessed through these products in a single step.
- Dutta, Uttam,Maity, Soham,Kancherla, Rajesh,Maiti, Debabrata
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supporting information
p. 6302 - 6305
(2015/02/19)
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- Combining silver catalysis and organocatalysis: A sequential michael addition/hydroalkoxylation one-pot approach to annulated coumarins
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A highly stereoselective one-pot procedure for the synthesis of five-membered annulated hydroxycoumarins has been developed. By merging primary amine catalysis with silver catalysis, a series of functionalized coumarin derivatives were obtained in good yields (up to 91%) and good to excellent enantioselectivities (up to 99% ee) via a Michael addition/hydroalkoxylation reaction. Depending on the substituents on the enynone, the synthesis of annulated six-membered rings is also feasible.
- Hack, Daniel,Chauhan, Pankaj,Deckers, Kristina,Hermann, Gary N.,Mertens, Lucas,Raabe, Gerhard,Enders, Dieter
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supporting information
p. 5188 - 5191
(2014/12/11)
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- Palladium nanoparticles catalyzed Sonogashira reactions for the one-pot synthesis of symmetrical and unsymmetrical diarylacetylenes
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A variety of symmetrical and unsymmetrical diarylacetylenes are synthesized by ligand-free palladium nanoparticles catalyzed copper-free and amine-free Sonogashira cross-coupling reactions between aryl iodides and trimethylsilylacetylene (TMSA) under mild reaction conditions.
- Mandali, Pavan Kumar,Chand, Dillip Kumar
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- Cooperative supramolecular polymerization driven by metallophilic Pd?Pd interactions
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A new oligophenyleneethynylene (OPE)-based Pd(II) pyridyl complex has been synthesized, and its self-assembly has been investigated in solution, in the bulk state, and on surfaces. Detailed analysis of concentration- and temperature-dependent UV-vis studies in methylcyclohexane supported by DFT calculations demonstrate for the first time that cooperative supramolecular polymerization processes can be driven by metallophilic interactions.
- Mayoral, María José,Rest, Christina,Stepanenko, Vladimir,Schellheimer, Jennifer,Albuquerque, Rodrigo Q.,Fernández, Gustavo
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p. 2148 - 2151
(2013/03/28)
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- K3PO4-KOH mixture as efficient reagent for the deprotection of 4-aryl-2-methyl-3-butyn-2-ols to terminal acetylenes
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A mixture of potassium hydroxide and potassium phosphate was found to be an active reagent mixture for the cleavage of 2-hydroxypropyl-protected acetylenes. The reaction was performed in toluene at reflux temperature and gave terminal acetylenes in good to excellent yields within very short periods of time. Numerous other functional groups are tolerated. Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for full experimental and spectral details.
- Smeyanov, Alexey,Schmidt, Andreas
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p. 2809 - 2816
(2013/08/23)
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- New hole transporting materials based on tetraphenylbenzene and aromatic amine derivatives for OLEDs
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Three different new hole transport compounds, namely,2-[1-{4-(N,N- diphenylamino) phenyl}-3,4,5,6-tetraphenylbenzene-2-yl]5-N,N- diphenylaminopyridine(DPAP-TB), 2-[1-{4-(N-phenylnaphthalene-1-amino)phenyl}-3, 4,5,6-tetraphenylbenzene-2-yl]5-(N-phenylnaphthalen-1-amino)pyridine(1-PNAP-TB) and 2-[1{4-(N-phenylnaphthal-en-1-amino)phenyl}-3,4-,5,6-tetraphenylbenzene-2- yl]-5-(N-phenylnaphthalen-2-amino)pyridine(2-PNAP-TB) were synthesized. Optical and electronic properties were examined by UV-Visible absorption spectrum and cyclic voltammetry. Luminance efficiencies and external quantum efficiencies of DPAP-TB, 1-PNAP-TB and 2-PNAP-TB were 3.72, 2.82, 3.30 cd/A, and 1.29, 0.97, 1.12% at 10 mA/cm2, respectively. Synthesized materials exhibited high Tg in the range of 118 to 133°C. These values are higher than that of NPB which is commonly used as a hole transporting material.
- Kim, Seungho,Lee, Sang-Ho,An, Byeong-Kwan,Oh, Se-Young,Kay, Kwang-Yol,Park, Jongwook
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- A photolabile protection strategy for terminal alkynes
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We present a strategy for photolabile protection of terminal alkynes. Several photo-caged alcohols were synthesized via mild copper(II)-catalyzed substitution between tertiary propargylic alcohols and 2-nitrobenzyl alcohol to build up robust, base stable o-nitrobenzyl (NB) photo-cleavable compounds. We compare the new photolabile protecting group with the commonly used alkyne protecting group, 2-methyl-3-butyn-2-ol and the results show that NB ethers are stable under the cleaving conditions for the cleavage of methylbutynol protected alkynes. Additionally, we present the synthesis of photo-cleavable NB derivatives containing thiol groups that can serve as agents for photoinduced surface functionalization reactions.
- Gschneidtner, Tina A.,Moth-Poulsen, Kasper
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p. 5426 - 5429
(2013/09/23)
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- Rhodium-catalyzed chemo- and regioselective cross-dimerization of two terminal alkynes
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Cross-dimerization of terminal arylacetylenes and terminal propargylic alcohols/amides has been achieved in the presence of a rhodium catalyst. This method features high chemo- and regioselectivities rendering convenient and atom economical access to functionalized enynes.
- Xu, Hua-Dong,Zhang, Ren-Wei,Li, Xiaoxun,Huang, Suyu,Tang, Weiping,Hu, Wen-Hao
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supporting information
p. 840 - 843
(2013/03/29)
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- One-pot, two-step conversion of aldehydes to phosphonyl- and sulfonylpyrazoles using Bestmann-Ohira reagent
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A one-pot, two-step, three-component method for the conversion of commercially available aldehydes to phosphonylpyrazoles has been developed, demonstrating, for the first time, the dual reactivity of the Bestmann-Ohira reagent (BOR) in a single-pot transformation. This method, extended to the synthesis of sulfonylpyrazoles by employing BOR in the first step and a diazomethyl sulfone in the second step, is complementary, with regard to regioselectivity, to the previous methods for the synthesis of such functionalized pyrazoles.
- Kumar, Rahul,Verma, Deepti,Mobin, Shaikh M.,Namboothiri, Irishi N. N.
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supporting information; experimental part
p. 4070 - 4073
(2012/09/21)
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- Copper-catalyzed highly selective semihydrogenation of non-polar carbon-carbon multiple bonds using a silane and an alcohol
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A copper catalyst bearing a suitable Xantphos derivative or NHC ligand was found to be highly efficient for the selective semihydrogenation of non-polar unsaturated compounds using a mixture of a silane and an alcohol as reducing agent. The catalytic system was useful for the selective semihydrogenation of internal alkynes to (Z)-alkenes with suppression of overreduction to the corresponding alkanes. Furthermore, semihydrogenations of terminal alkyne, 1,2-diene, 1,3-diene, 1,3-enyne and 1,3-diyne systems were also achieved selectively. Copyright
- Semba, Kazuhiko,Fujihara, Tetsuaki,Xu, Tinghua,Terao, Jun,Tsuji, Yasushi
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p. 1542 - 1550
(2012/08/08)
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