- Photocatalyzed Diastereoselective Isomerization of Cinnamyl Chlorides to Cyclopropanes
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Endergonic isomerizations are thermodynamically unfavored processes that are difficult to realize under thermal conditions. We report a photocatalytic and diastereoselective isomerization of acyclic cinnamyl chlorides to strained cyclopropanes. Quantum mechanical calculations (uM06-2X and DLPNO), including TD-DFT calculations, and experimental studies provide evidence for the energy transfer from an iridium photocatalyst to the allylic chloride substrate followed by C-Cl homolytic cleavage. Subsequent Cla¢ radical migration forms a localized triplet 1,3-diradical intermediate that, after intersystem crossing, undergoes ring-closing to form the desired product. The mild reaction conditions are compatible with a broad range of functional groups to generate chlorocyclopropanes in high yields and diastereoselectivities. A more efficient process is developed by addition of a catalytic amount of a nickel complex, and we propose a novel role for this cocatalyst to recycle an allyl chloride byproduct generated in the course of the reaction. The reaction is also shown to be stereoconvergent, as an E/Z mixture of cinnamyl chlorides furnish the anti-chlorocyclopropane product in high diastereoselectivity. We anticipate that the use of a visible light activated photocatalyst to transform substrates in combination with a transition metal catalyst to recycle byproducts back into the catalytic cycle will provide unique opportunities for the discovery of new reactivity.
- Dykstra, Ryan,Gutierrez, Osvaldo,Martin, Robert T.,Tambar, Uttam K.,Troian-Gautier, Ludovic,Xu, Bin
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supporting information
p. 6206 - 6215
(2020/04/27)
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- Catalytic Generation and Chemoselective Transfer of Nucleophilic Hydrides from Dihydrogen
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Copper(I)–N-heterocyclic-carbene (NHC) complexes enabled the catalytic generation of nucleophilic hydrides from dihydrogen (H2) and their subsequent transfer to allylic chlorides. The highly chemoselective catalyst displayed no concomitant hydrogenation reactivity; in fact, the terminal double bond formed in the hydride transfer remained intact. Switching to deuterium gas (D2) allowed for regioselective monodeuteration with excellent isotope incorporation.
- Pape, Felix,Brechmann, Lea T.,Teichert, Johannes F.
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supporting information
p. 985 - 988
(2019/01/04)
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- Rhodium(ii)-catalyzed intramolecular formal [4 + 3] cycloadditions of dienyltriazoles: Rapid access to fused 2,5-dihydroazepines
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Rhodium(ii)-catalyzed intramolecular [4 + 3] cycloadditions of dienyltriazoles have been developed, which enable the efficient synthesis of various fused 2,5-dihydroazepines. Mechanistically, the titled reaction proceeds via an interesting tandem cyclopropanation/aza-cope rearrangement.
- Tian, Yu,Wang, Yuanhao,Shang, Hai,Xu, Xudong,Tang, Yefeng
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supporting information
p. 612 - 619
(2015/02/05)
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- Physical properties and excellent thermal stability microporous polyolefin film temp.
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The present invention relates to a microporous polyolefin film suitable as a separator for batteries and thermal properties thereof. A microporous polyolefin film according to the present invention has a film thickness of 5-40 μm, a porosity of 30%-60%, a permeability of 2.0x10 -5 -8.0x10 -5 Darcy, a maximum pore size determined by the bubble point method of not more than 0.1 μm, a puncture strength of 0.20 N/μm or more at room temperature and 0.05 N/μm or more at 120°C, and a maximum shrinkage ratio in the transverse direction (TD) when subjected to a thickness-normalized external force in TMA (thermo-mechanical analysis) of not more than 0%. With excellent thermal stability at high temperature as well as superior puncture strength and gas permeability, the microporous polyolefin film according to the present invention is suitable for high-capacity,and high-power batteries.
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- Direct conversion of aldehydes and ketones to allylic halides by a NbX 5-[3,3] rearrangement
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Sequential addition of vinylmagnesium bromide and NbCl5, or NbBr5, to a series of aldehydes and ketones directly provides homologated, allylic halides. Transposition of the intermediate vinyl alkoxide is envisaged through a metalo-halo-[3,3] rearrangement with concomitant delivery of the halogen to the terminal carbon. The [3,3] rearrangement is equally effective for the conversion of a propargyllic alcohol to the corresponding allenyl bromide. Georg Thieme Verlag Stuttgart.
- Fleming, Fraser F.,Ravikumar,Yao, Lihua
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experimental part
p. 1077 - 1080
(2009/09/29)
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- Allylic and allenic halide synthesis via NbCl5- and NbBr 5-mediated alkoxide rearrangements
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(Chemical Equation Presented) Addition of NbCl5 or NbBr 5 to a series of magnesium, lithium, or potassium allylic or propargylic alkoxides directly provides allylic or allenic halides. Halogenation formally occurs through a metallahalo-[3,3] rearrangement, although concerted, ionic, and direct displacement mechanisms appear to operate competitively. Transposition of the olefin is equally effective for allylic alkoxides prepared by nucleophilic addition, deprotonation, or reduction. Experimentally, the niobium pentahalide halogenations are rapid, afford essentially pure (E)-allylic or -allenic halides after extraction, and are applicable to a range of aliphatic and aromatic alcohols, aldehydes, and ketones. 2009 American Chemical Society.
- Ravikumar,Yao, Lihua,Fleming, Fraser F.
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supporting information; experimental part
p. 7294 - 7299
(2010/01/16)
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- Synthesis of novel diazatricyclodecanes (DTDs). Effects of structural variation at the C3′ allyl end and at the phenyl ring of the cinnamyl chain on μ-receptor affinity and opioid antinociception
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Two series of analogues of 9-propionyl-10-cinnamyl-9,10-diazatricyclo[4.2.1.12,5]decane (1a) and 2-propionyl-7-cinnamyl-2,7-diazatricyclo[4.4.0.03,8]decane (2a), in which the cinnamyl moiety was replaced by various aralkenyl chains,
- Pinna, Gerard Aime,Cignarella, Giorgio,Ruiu, Stefania,Loriga, Giovanni,Murineddu, Gabriele,Villa, Stefania,Grella, Giuseppe Enrico,Cossu, Gregorio,Fratta, Walter
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p. 4015 - 4026
(2007/10/03)
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- N-3(9)-arylpropenyl-N-9(3)-propionyl-3,9-diazabicyclo[3.3.1]nonanes as μ-opioid receptor agonists. Effects on μ-affinity of arylalkenyl chain modifications
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Two series of N-3-arylpropenyl-N-9-propionyl-3,9-diazabicyclo[3.3.1]nonanes (1b-j) and of the reverted N-3-propionyl-N-9-arylpropenyl isomers (2b-j) as analogues of the previously reported analgesic N-3(9)-cinnamyl-N-9(3)-propionyl-3,9-diazabicyclo[3.3.1]nonanes (DBN) (1a, 2a) were synthesised and their affinity and selectivity towards opioid μ-, δ- and κ-receptors were evaluated. Several compounds (1e,i,j-2d,e,f,g,j) exhibited a μ-affinity in the low nanomolar range with moderate or negligible affinity towards δ- and κ-receptors. The representative term N-9-(3,3-diphenylprop-2-enyl)-N-3-propionyl-DBN (2d) displayed in vivo (mouse) a potent analgesic effect (ED50 3.88 mg/kg ip) which favourably compared with that of morphine (ED50 5 mg/kg ip). In addition, 2d produced in mice tolerance after a period twice as long with morphine.
- Pinna, Gérard A.,Cignarella, Giorgio,Loriga, Giovanni,Murineddu, Gabriele,Mussinu, Jean-Mario,Ruiu, Stefania,Fadda, Paola,Fratta, Walter
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p. 1929 - 1937
(2007/10/03)
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- Triphenylamine derivative, charge-transporting material comprising the same, and electrophotographic photoreceptor
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A triphenylamine derivative, represented by the following general formula (1): STR1 wherein R1, R2, R3, R4, R5 and R6 each represents a hydrogen atom, a lower alkyl group, an alkoxy group, a halogen atom or an aryl group which may have a substituent group; and m and n each represents 0 or 1.
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- Phenothiazine or phenoxazine derivative, charge-transporting material comprising the same, and electrophotographic photoreceptor
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A phenothiazine or phenoxazine derivative represented by the following general formula (1), a charge-transporting material comprising the derivative, and an electrophotographic photoreceptor containing the charge-transporting material are disclosed. The charge-transporting material has good solubility in binder polymers, satisfactory sensitivity, and a low residual potential In general formula (1) Ar1 and Ar2 may be the same or different and each represents an optionally substituted aryl group; R1 and R2 may be the same or different and each represents a hydrogen atom, a lower alkyl group, or an optionally substituted aryl group; R3 represents a lower alkyl group, an alicyclic hydrocarbon group having 5 to 7 carbon atoms, an optionally substituted aryl group, or an optionally substituted aralkyl group; X represents a sulfur atom or an oxygen atom; and n and m each represents an integer of 0 or 1.
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- Inhibitors of microsomal triglyceride transfer protein and method
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Compounds are provided which inhibit microsomal triglyceride transfer protein and thus are useful for lowering serum lipids and treating atherosclerosis and related diseases. The compounds have the structure STR1 wherein R1 to R7, Q, X and Y are as defined herein.
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- Carbazole derivative charge transporting material using the same and electrophotographic photoreceptor
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A charge transporting material high in solubility in a binder polymer and having high carrier mobility is disclosed, which contains a carbazole derivative represented by the following general formula (1): STR1 wherein Ar1 and Ar2, which may be the same or different, each represents an aryl group which may have a substituent group; R1 and R2, which may be the same or different, each represents a lower alkyl group or an aryl group which may have a substituent group; R3 represents a lower alkyl group, an alicyclic alkyl group having 5 to 7 carbon atoms, an aryl group which may have a substituent group, or an aralkyl group which may have a substituent group; and m and n each represents an integer of 0 or 1. An electrophotographic photoreceptor containing the charge transporting material is also disclosed.
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- Nucleic acids encoding microsomal trigyceride transfer protein
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Nucleic acid sequences, particularly DNA sequences, coding for all or part of the high molecular weight subunit of microsomal triglyceride transfer protein, expression vectors containing the DNA sequences, host cells containing the expression vectors, and methods utilizing these materials. The invention also concerns polypeptide molecules comprising all or part of the high molecular weight subunit of microsomal triglyceride transfer protein, and methods for producing these polypeptide molecules. The invention additionally concerns novel methods for preventing, stabilizing or causing regression of atherosclerosis and therapeutic agents having such activity. The invention concerns further novel methods for lowering serum liquid levels and therapeutic agents having such activity.
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- Triphenylamine derivative, charge-transporting material comprising the same, and electrophotographic photoreceptor
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A triphenylamine derivative, a charge-transporting material comprising the triphenylamine derivative, and an electrophotographic photoreceptor containing a charge-transporting layer comprising the triphenylamine derivative are disclosed, wherein the triphenylamine derivative is represented by the following general formula (1): STR1 wherein R1, R2, R3, R4, and R5 may be the same or different and each represents a hydrogen atom, a lower alkyl group, an alkoxy group, a halogen atom, or an aryl group which may have a substituent, or R1 and R2 and/or R3 and R4 may be taken together to form a ring, and n represents 0 or 1.
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- Regioselective Synthesis of Allyltrimethylsilanes from Allylic Halides and Allylic Sulfonates. Application to the Synthesis of 2,3-Bis(trimethylsilyl)alk-1-enes
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The preparation of allyltrimethylsilanes by regioselective pathways is described.Treatment of (E)-1-chloro-2-alkenes with a reagent prepared from 1 equiv each of trimethylsilyllithium and copper(I) iodide in hexamethylphosphoramide to presumably form a (trimethylsilyl)copper reagent affords 3-(trimethylsilyl)-1-alkenes in good to excellent yields with a high regioselectivity.Treatment of these same 1-chloro-2-alkenes with (trimethylsilyl)lithium alone without added copper(I) iodide yields only (E)-1-(trimethylsilyl)-2-alkenes.A single allylic halide thus yields two regioisomeric allyltrimethylsilanes by proper choice of reaction conditions.The reaction of a variety of allylic sulfonates with (trimethylsilyl)copper has also been investigated.The mesylates of 2 deg and 3 deg allylic alcohols yield mixtures of isomeric allyltrimethylsilanes in which the 1-(trimethylsilyl)-2-alkenes predominate.With geraniol, the mesylate was prepared in situ and allowed to react with (trimethylsilyl)copper to afford two isomeric allyltrimethylsilanes in which the 3-(trimethylsilyl)-1-alkene predominates.Finally, these reactions have also been used to prepare a variety of 2,3-bis(trimethylsilyl)alk-1-enes, a class of unsaturated organosilanes which has received little attention in the literature.
- Smith, Janice Gorzynski,Drozda, Susan E.,Petraglia, Susan P.,Quinn, Nina R.,Rice, Elizabeth M.,et al.
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p. 4112 - 4120
(2007/10/02)
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