- NON-AQUEOUS CYANATION OF HALIDES USING LITHIUM CYANIDE
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Efficient conversion of various halides into the corresponding nitriles with lithium cyanide in tetrahydrofuran is described.
- Harusawa, Shinya,Yoneda, Ryuji,Omori, Yukie,Kurihara, Takushi
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- Lithium Cyanide Supported by O- and N-Donors
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A series of adducts of LiCN, namely [Li(Me2CO3)CN], [Li(Et2CO3)CN], and [Li(NMP)CN] (NMP = N-methyl-2-pyrrolidone) were prepared by treatment of solvent-free LiCN with the appropriate donor. The starting material for these approaches, donor-free LiCN, was quantitatively prepared from Me3SiCN and Li[Me] in diethyl ether at 0 °C. Alternatively, [Li(NMP)CN] was synthesized by metathesis reaction of LiCl with NaCN in the presence of stoichiometric amounts of NMP. Although [Li(Me2CO3)CN] and [Li(Et2CO3)CN] are water-sensitive compounds and decompose at the exposure to air, [Li(NMP)CN] is stable in air, even at elevated temperatures. The thermal stability of [Li(NMP)CN] was proven by differential thermal analysis (DTA). [Li(NMP)CN] shows thermal stability up to temperatures of about 132 °C. To evaluate the cyanation ability the reactions of 1-bromooctane and 3-bromocyclohexene with unsupported LiCN, [Li(NMP)CN], and a mixture of NaCN/LiCl/NMP were investigated. We found that [Li(NMP)CN] as well as LiCl/NaCN/NMP are efficient cyanation reagents comparable to the expensive and air-sensitive, donor-free LiCN. A product of the chloride-cyanide-bromide exchange could be isolated and structurally characterized by X-ray diffraction.
- Budanow, Alexandra,Franz, Klaus-Dieter,Vitze, Hannes,Fink, Lothar,Alig, Edith,Bolte, Michael,Wagner, Matthias,Lerner, Hans-Wolfram
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- Michael addition of cyanide to cyclohex-1-enyliodonium salts
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Reaction of 4-substituted cyclohex-1-enyliodonium salt with cyanide in chloroform produces three isomeric cyanocyclohexenes, ipso and two cine products. Deuterium labeling experiments showed that the allylic cine product is formed via the Michael addition of cyanide, followed by elimination of the iodonio group and a 1,2-H shift.
- Fujita, Morifumi,Kim, Wan Hyeok,Okuyama, Tadashi
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- Electrophilic cyanation of allylic boranes: Synthesis of β,γ-unsaturated nitriles containing allylic quaternary carbon centers
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The electrophilic cyanation of allylic boranes, a process that is applicable to the construction of allylic quaternary carbon centers, is reported. The reaction has a broad substrate scope with a high functional group tolerance. The results represent an u
- Kiyokawa, Kensuke,Hata, Shotaro,Kainuma, Shunpei,Minakata, Satoshi
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p. 458 - 461
(2019/01/10)
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- (Guanidine)copper Complex-Catalyzed Enantioselective Dynamic Kinetic Allylic Alkynylation under Biphasic Condition
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Highly enantioselective allylic alkynylation of racemic bromides under biphasic condition is furnished in this report. This approach employs functionalized terminal alkynes as pro-nucleophiles and provides 6- and 7-membered cyclic 1,4-enynes with high yields and excellent enantioselectivities (up to 96% ee) under mild conditions. Enantioretentive derivatizations highlight the synthetic utility of this transformation. Cold-spray ionization mass spectrometry (CSI-MS) and X-ray crystallography were used to identify some catalytic intermediates, which include guanidinium cuprate ion pairs and a copper-alkynide complex. A linear correlation between the enantiopurity of the catalyst and reaction product indicates the presence of a copper complex bearing a single guanidine ligand at the enantio-determining step. Further experimental and computational studies supported that the alkynylation of allylic bromide underwent an anti-SN2′ pathway catalyzed by nucleophilic cuprate species. Moreover, metal-assisted racemization of allylic bromide allowed the reaction to proceed in a dynamic kinetic fashion to afford the major enantiomer in high yield.
- Cui, Xi-Yang,Ge, Yicen,Tan, Siu Min,Jiang, Huan,Tan, Davin,Lu, Yunpeng,Lee, Richmond,Tan, Choon-Hong
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supporting information
p. 8448 - 8455
(2018/06/22)
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- Nickel(0)-catalyzed asymmetric hydrocyanation of 1,3-dienes
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1,2-Bis-diarylphosphinites are excellent ligands for the Ni(0)-catalyzed hydrocyanation of certain types of 1,3-dienes. 1-Phenyl-1,3-butadiene, 1-vinyl-3,4-dihydronaphthalene, and 1-vinylindene undergo highly regioselective hydrocyanation under ambient co
- Saha, Biswajit,RajanBabu
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p. 4657 - 4659
(2007/10/03)
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- Michael addition-elimination mechanism for nucleophilic substitution reaction of cycloalkenyl iodonium salts and selectivity of 1,2-hydrogen shift in cycloalkylidene intermediate
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(Chemical Equation Presented) Reactions of cyclohexenyl and cyclopentenyl iodonium salts with cyanide ion in chloroform give cyanide substitution products of allylic and vinylic forms. Deuterium-labeling experiments show that the allylic product is formed via the Michael addition of cyanide to the vinylic iodonium salt, followed by elimination of the iodonio group and 1,2-hydrogen shift in the 2-cyanocycloalkylidene intermediate. The hydrogen shift preferentially occurs from the methylene rather than the methine β-position of the carbene, and the selectivity is rationalized by the DFT calculations. The Michael reaction was also observed in the reaction of cyclopentenyliodonium salt with acetate ion in chloroform. The vinylic substitution products are ascribed to the ligand-coupling (via λ3-iodane) and elimination-addition (via cyclohexyne) pathways.
- Fujita, Morifumi,Wan, Hyeok Kim,Fujiwara, Koji,Okuyama, Tadashi
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p. 480 - 488
(2007/10/03)
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- (2-hydroxy)ethyl-thioureas useful as modulators of alpha2B adrenergic receptors
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Compounds of formula (i) and of formula (ii) wherein the symbols have the meaning disclosed in the specification, specifically or selectively modulate α2B and/or α2C adrenergic receptors in preference over α2A adrenergic receptors, and as such are useful for alleviating chronic pain and allodynia and have no or only minimal cardivascular and/or sedatory activity.
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- Stereoselective synthesis of a conformationally defined cyclohexyl carnitine analogue that binds CPT-1 with high affinity
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Carnitine (1, 3-hydroxy-4-trimethylammoniobutyrate) is important in mammalian tissue as a carrier of acyl groups. In order to explore the binding requirements of the carnitine acyltransferases for carnitine, we designed conformationally defined cy- clohexyl carnitine analogues. These diastereomers contain the required gauche conformation between the trimethylammonium and hydroxy groups but vary the conformation between the hydroxy and carboxylic acid groups. Here we describe the synthesis and biological activity of the all-trans diastereomer (2), which was prepared by the ring opening of trans-methyl 2,3-epoxycylohex- anecarboxylate with NaN3 . Racemic 2 was a competitive inhibitor of neonatal rat cardiac myocyte CPT-1 (K(i) 0.5 mMfor racemic 2; K(m) 0.2 mM for L-carnitine) and a noncompetitive inhibitor of neonatal rat cardiac myocyte CPT-2 (K(i) 0.67 mM). These results suggest that 2 represents the bound conformation of carnitine for CPT-1. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.
- Hutchison, Tracy L.,Saeed, Ashraf,Wolkowicz, Paul E.,McMillin, Jeanie B.,Brouillette, Wayne J.
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p. 1505 - 1511
(2007/10/03)
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- Diastereoselectivity in the epoxidation of substituted cyclohexenes by dimethyldioxirane
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Three series of compounds based on the cyclohexene framework have been epoxidized by dimetbyldioxirane. A pronounced dependence of epoxide diastereoselectivity on substituent has been observed. In addition there is a solvent influence on this stereoselectivity. The results have been explained by invoking steric, H-bonding, and dipole - dipole influences on the epoxide stereochemistry.
- Murray, Robert W.,Singh, Megh,Williams, Brian L.,Moncrieff, Hazel M.
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p. 1830 - 1841
(2007/10/03)
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- Cyanation of Allylic Carbonates and Acetates Using Trimethylsilyl Cyanide Catalyzed by Palladium Complex
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Allylic carbonates and acetates are cyanated with trimethylsilyl cyanide in the presence of a catalytic amount (5 mol percent based on the allylic substrates) od Pd(PPh3)4 or Pd(CO)(PPh3)3 in THF under reflux to afford β,γ-unsaturated nitriles in high yields.
- Tsuji, Yasushi,Yamada, Naoaki,Tanaka, Shinsuke
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- Formamidine anions in synthesis. The one-carbon homologation of aldehydes and ketones to nitriles
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Treatment of various carbonyl compounds with the carbanion of the 2-trimethylsilymethyl formamidine 2 gives the enamidine 3 which is readily transformed into the homologated nitriles 6.
- Santiago,Meyers
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p. 5839 - 5842
(2007/10/02)
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- Dephosphorylation of Cyano Diethyl Phosphates by Reduction with Lithium-Liquid Ammonia: An Efficient Method for Conversion of Carbonyl Compounds into Nitriles
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Cyano diethyl phosphate derivatives of aromatic carbonyl compounds and α,β-unsaturated ketones were successively dephosphorylated by reduction with lithium in liquid ammonia followed by treatment with isoprene or alkyl halides to give β,γ-unsaturated nitriles or α-alkyl-β,γ-unsaturated nitriles in moderate to good yields.
- Yoneda, Ryuji,Osaki, Takahiro,Harusawa, Shinya,Kurihara, Takushi
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p. 607 - 610
(2007/10/02)
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- Nickel- and Palladium-Catalyzed Additions of Nucleophiles to Cyclic 1,3-Dienes
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Carbon nucleophiles have been found to add smoothly to 1,3-cyclohexadiene using either a preformed nickel-ligand complex or Ni(0) prepared by in situ reduction of Ni(II) in the presence of a ligand to give 1,2- and 1,4-addition products.Analogous adducts were also obtained from 1,3-cyclopentadiene and 1,3-cyclooctadiene, but the yields were considerably lower.Attempts to add benzenesufinic acid to 1,3-cyclohexadiene using Ni(0) were unsuccessful; this reaction was instead found to be catalyzed by Pd(0)-phosphite complexes.
- Andell, Ove S.,Baeckvall, Jan-E.,Moberg, Christina
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p. 184 - 189
(2007/10/02)
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- HOMOLYTIC DISPLACEMENT AT CARBON. X. TOLUENESULPHONYL IODIDE AS A SOURCE OF TOLUENESULPHONYL RADICALS FOR THE FORMATION OF ALLYL-, BENZYL-, CYCLOPROPYLCARBINYL-, SPIROCYCLOPROPYLCYCLOALKYL-, BICYCLOALKYL-, AND BICYCLOALKYL-4-TOLYLSULPHONES FROM ORGANOCOBALOXIMES
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4-Toluenesulphonyl iodide reacts thermally at alkylsulphone.Spiro- and bicyclo-alkyl compounds are also formed with other free radical precursors.The reactions are believed to take place through a chain mechanism in which cobaloxime(II), present adventitiously or formed by partial homolysis of the substrate, abstracts iodine from the toluenesulphonyl iodide to give the toluenesulphonyl radical, which attacks the organic ligand of the cobaloxime, preferably at the terminal olefinic carbon, thereby displacing cobaloxime(II) and giving the observed organic product.
- Ashcroft, Martyn R.,Bougeard, Peter,Bury, Adrian,Cooksey, Christopher J.,Johnson, Michael D.
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p. 403 - 416
(2007/10/02)
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- Stereochemistry and Mechanism of the Nickel-catalysed Hydrocyanation of Conjugated Dienes
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Nickel-catalysed addition of deuterium cyanide to cyclohexa-1,3-diene was shown to occur with cis stereochemistry, indicating that a cis-migration of co-ordinated cyanide takes place in an intermediate ?-allylnickel complex.
- Baeckvall, Jan-E.,Andell, Ove S.
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p. 260 - 261
(2007/10/02)
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- Zum thermischen Verhalten einiger 1-(Tricyclo2,7>hept-1-yl)aziridine
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The reaction of 1-chlorotricyclo2,7>heptane (1) and lithium aziridides 4 led to the formation of the 1-(tricyclohept-1-yl)aziridines 5a - d which, on thermolysis, decomposed to the carbonitrile 10 and (stereospecifically) to the respective olefin 11.A retro-carbene ringopening reaction of the bicyclobutane unit in 5 forming 13 as an intermediate is proposed as mechanistic pathway.
- Zoch, Hans-Georg,Kinzel, Elke,Szeimies, Guenter
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p. 968 - 974
(2007/10/02)
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