- A New Preparative Method for α,β-Unsaturated Nitriles by the Palladium-catalysed Decarboxylation-Dehydrogenation of Allyl α-Cyanocarboxylates
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Allyl α-cyanocarboxylates, derived from cyanoacetic acid, were converted into α,β-unsaturated nitriles in the presence of a palladium catalyst.
- Minami, Ichiro,Yuhara, Masami,Shimizu, Isao,Tsuji, Jiro
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- Cyanation of 1-Halocycloalkenes Catalyzed by Tetracyanocobaltate(I). Convenient Synthesis of 1-Cyanocycloalkenes
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1-Cyanocycloalkenes (1-cyanocyclopentene, -hexene, -heptene, and -octene) were readily synthesized by catalytic cyanation of the corresponding 1-halocycloalkenes with tetracyanocobaltate(I).Reactivities of methyl-substituted 1-chlorocyclohexenes were lower than that of 1-chlorocyclohexene, and 1-chloro-2-methylcyclohexene scarecely reacted.Hydrogenation and isomerization of 1-cyanocycloalkenes were observed only with 1-cyanocycloheptene and 1-cyano-6-methylcyclohexene, respectively.
- Funabiki, Takuzo,Kishi, Hirohito,Sato, Yoshihiro,Yoshida, Satohiro
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- Amide α,β-Dehydrogenation Using Allyl-Palladium Catalysis and a Hindered Monodentate Anilide
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A practical and direct method for the α,β-dehydrogenation of amides is reported using allyl-palladium catalysis. Critical to the success of this process was the synthesis and application of a novel lithium N-cyclohexyl anilide (LiCyan). The reaction conditions tolerate a wide variety of substrates, including those with acidic heteroatom nucleophiles.
- Chen, Yifeng,Turlik, Aneta,Newhouse, Timothy R.
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supporting information
p. 1166 - 1169
(2016/02/18)
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- Palladium-Catalyzed α,β-Dehydrogenation of Esters and Nitriles
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A highly practical and general palladium-catalyzed methodology for the α,β-dehydrogenation of esters and nitriles is reported. Generation of a zinc enolate or (cyanoalkyl)zinc species followed by the addition of an allyl oxidant and a palladium catalyst results in synthetically useful yields of α,β-unsaturated esters, lactones, and nitriles. Preliminary mechanistic investigations are consistent with reversible β-hydride elimination and turnover-limiting, propene-forming reductive elimination.
- Chen, Yifeng,Romaire, Justin P.,Newhouse, Timothy R.
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supporting information
p. 5875 - 5878
(2015/05/27)
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- A chemoenzymatic synthesis of an androgen receptor antagonist
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A new scalable enzymatic resolution approach to both enantiomers of trans-2-hydroxycyclohexanecarbonitrile (9 and 11) was developed. Treatment of the racemic mixture (4) with succinic anhydride in the presence of Novozym 435 led to selective acylation of one enantiomer to the corresponding hemisuccinate, which was separated from the unreacted enantiomer by a simple basic extraction. This procedure produced the desired enantiomer in high ee, while obviating the need for chromatography or expensive catalysts and ligands. The application of this protocol to the large-scale synthesis of an androgen receptor antagonist (1) is described.
- Vaidyanathan, Rajappa,Hesmondhalgh, Lynsey,Hu, Shanghui
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p. 903 - 906
(2012/12/30)
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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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- Tandem alkylation-cyclization process via an O,C-dianion
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A general protocol for preparing densely functionalized cyclopentenones through a tandem nucleophilic addition-deprotonation-alkylation-cyclization process is described. Addition of lithioallene 2 to enamides 1 generates tetrahedral intermediate 3. Deprotonation of the γ carbon atom of the allene function in situ, followed by trapping by a suitable electrophile and cyclization during workup leads to C6 substituted cyclopentenones 6.
- Banaag, April R.,Berger, Gideon O.,Dhoro, Francis,Delos Santos, Derrick B.,Dixon, Darryl D.,Mitchell, James P.,Tokeshi, Bradley K.,Tius, Marcus A.
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p. 3419 - 3428
(2007/10/03)
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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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p. 382 - 383
(2007/10/03)
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- A new conversion of primary nitro compounds into nitriles
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The reaction of primary nitro compounds with isocyanides and isocyanates in the presence of a base leads to a new preparation of nitriles. The reaction probably proceeds through the in situ formation of a nitrile oxide followed by a fast oxygen transfer with the isocyanide. Combined with the Knovenagel addition of nitromethane to cyclic ketone, this reaction brings a highly effective regioselective formation of cyclic α-β unsaturated nitriles.
- El Kaim, Laurent,Gacon, Ariane
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p. 3391 - 3394
(2007/10/03)
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- A convenient and stereoselective synthesis of alk-2-enenitriles
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A convenient and stereoselective synthesis of alk-2-enenitriles based on the reaction of readily available S-(β-oxoalkyl)thiophosphates and Se-(β-oxoalkyl)selenophosphates with potassium cyanide in the presence of 18-crown-6 is described.
- Dybowski, Piotr,Skowrońska, Aleksandra
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p. 284 - 286
(2007/10/03)
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- The Cyanation of Vinyl Halides with Alkali Cyanides Catalyzed by Nickel(0)-Phosphine Complexes Generated In Situ: Synthetic and Stereochemical Aspects
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The cyanation of β-bromostyrenes catalyzed by Ni(PPh3)n, which was generated in situ from NiBr2(PPh3)2-Zn-PPh3 (Ni:Zn:P=1:3:2 molar ratio), was at first examined with various MCN (M=K, Na)-dipolar aprotic solvent systems by several procedures.The presence of excess cyanide ion inhibited the reaction.However, when the KCN-DMF system with some intermediate cyanide solubility was used, the nitriles were obtained in high yields and high stereoselectivity at 50 deg C by almost all of the procedures attempted.On the contrary, the KCN-HMPA and KCN-MeCN systems with cyanide solubilities accelerated the coupling of the halides to inhibit the cyanation, and in general the NaCN-DMF and NaCN-HMPA systems with high cyanide solubilities needed to reduce Ni(II) before adding MCN in order to make the catalytic reaction start.Vinyl halides such as 1- and 2-halo (Cl, Br)-1-alkenes, 2-bromo-2-butenes, 3-bromo-3-hexenes, and 1-chlorocyclohexene were also cyanated using suitable procedures and MCN-solvent systems to give the corresponding nitriles in high yields and fair-to-good stereoselectivities.However, with (Z)-2-ethoxy-1-bromoethene the (E)-nitrile, though its selectivity markedly varied with the reaction temperature, was obtained as the main product.The cyanation of ethyl (Z)-β-bromoacrylate and ethyl α-bromoacrylate was unsuccessful due to polymerization.
- Sakakibara, Yasumasa,Enami, Hiroji,Ogawa, Hiroshi,Fujimoto, Shinpei,Kato, Hiroyuki,et al.
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p. 3137 - 3144
(2007/10/03)
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- Addition of diphenylphosphine to Michael-type olefins: the preparation of phosphine-nitrile and phosphine-ester ligands
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The reactions of five Michael-type olefins with diphenylphosphine have been carried out. 1-Cyanocyclopentene, 1-cyanocyclohexene, and 4-t-butyl-1-cyanocyclohexene all provide the corresponding 2-diphenylphosphino-1-cyanocycloalkanes, and both methyl acrylate and ethyl methacrylate yield to corresponding 2-diphenylphosphinopropionates.For the products from 1-cyanocyclopentene and 1-cyanocyclohexene, 13C and 31P NMR data are consistent with the formation of both trans (Ph2P equatorial and CN axial) and cis (both Ph2P and CN equatorial) isomers.The morpholine amide of 3-diphenylphosphinopropionic acid has been obtained by treatment of methyl-3-diphenylphosphinopropionate with the dimethylaluminum adduct of morpholine.This phosphine, Ph2Pmorph, has been isolated as its palladium(II) complex, (Ph2Pmorph)2PdCl2.A phosphine-benzaldimine, Ph2P(CH2)3NC(H)C6H5, has been obtained by reacting Ph2P(CH2)3NH2, from the reduction of PhP(CH2)2CN, with benzaldehyde in the presence of molecular sieves.
- Blinn, D.A.,Button, R.S.,Farazi, V.,Neeb, M.K.,Tapley, C.L.,et al.
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p. 143 - 152
(2007/10/02)
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- One-pot Conversion of Allylic Nitro Compounds Into Nitriles with Carbon Disulphide under Phase-transfer Catalysis Conditions
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An one-pot synthesis of allylic nitriles 3 from the corresponding nitro derivatives 1 is described.In the first step the substrates 1 are reduced to the oximes 2 by carbon disulphide in the presence of wet potassium carbonate, in solid-liquid PTC conditions.In the second, the formed oximes 2 are dehydrated by adding more CS2 and 15percent aqueous NaOH.
- Albanese, Domenico,Landini, Dario,Penso, Michele,Pozzi, Gianluca
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p. 965 - 971
(2007/10/02)
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- New Methods for the Syntheses of α,β-Unsaturated Ketones, Aldehydes, and Nitriles by the Palladium-Catalyzed Reactions of Allyl β-Oxo Esters, Allyl 1-Alkenyl Carbonates, and Allyl α-Cyano Esters
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Allyl β-oxo esters, allyl 1-alkenyl carbonates, and allyl α-cyano esters are converted into α,β-unsaturated ketones, aldehydes, and nitriles by palladium-catalyzed intramolecular decarboxylation-dehydrogenation.Palladium-phosphine complexes such as Pd(OAc)2-PPh3, Pd(OAc)2-dppe, or Pd2(dba)3*CHCl3-PPh3, are effective catalysts.Yields depend on solvents and on the mole ratio of palladium to phosphine.The optimum Pd/P ratio for each substrate was determined.Use of nitriles as solvents is essential for the dehydrogenation.
- Minami, Ichiro,Nisar, Mohammad,Yuhara, Masami,Shimizu, Isao,Tsuji, Jiro
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p. 992 - 998
(2007/10/02)
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- Ring Closures with α-Chloroazines
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Two series of unsymmetrical 3,6-disubstituted 1,2,3,4-tetrahydro-1,2,4,5-tetrazines and 3,5-disubstituted 4-amino-2,3-dihydro-1,2,4-triazoles were synthesized from unsymetrical 1,4-disubstituted 1-chloroazines with hydrazine, 1-methylhydrazine, and 1,2-dimethylhydrazine.These partially reduced heterocycles belong to little known and less accessible classes of heterocycles.
- Pilgram, Kurt H.,Skiles, Richard D.
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p. 1265 - 1268
(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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- Photochemistry of Succinimides with a Cycloalkenylalkyl Group in the Side Chain. Competitive Norrish Type II and Paterno-Buchi Reactions
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Photolysis of N-succinimides (9c-f) (m>/=2) afforded mainly azepinediones (13c-f) with ring enlargement as the Norrish type II cyclization products.In the case of m=1, spiro-azepinedione derivatives (11a, b) were obtained in addition to tricyclic nitrogen heterocycles (10a, b), the Norrish type II products.These spiro-azepinediones are probably formed via imide imide-oxetanes by the intramolecular Paterno-Buchi reaction of these succinimides in competition with the type II processes.Keywords: N-succinimide; Norrish type II reaction; oxetane formation; azepinedione; spiro compound; photochemistry.
- Machida, Minoru,Oda, Kazuaki,Kanaoka, Yuichi
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p. 950 - 956
(2007/10/02)
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- THE CYANATION OF VINYL HALIDES CATALYZED BY NICKEL(0) COMPLEX GENERATED IN SITU
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Nickel(0) species generated in situ from NiBr2(PPh3)2-Zn-PPh3 catalyzed the formation of unsaturated nitriles from vinyl halides and potassium cyanide.The reaction proceeded under very mild conditions and was stereoselective.
- Sakakibara, Yasumasa,Yadani, Nobuichi,Ibuki, Ichiro,Sakai, Mutsuji,Uchino, Norito
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p. 1565 - 1566
(2007/10/02)
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- Cyanoselenenylation of Olefins
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The reaction of simple olefins with phenyl selenocyanate in the presence of a Lewis acid provided 2-phenylseleno carbonitriles, the vicinal cyanoselelenylation products, stereoselectively in excellent yields.
- Tomoda, Shuji,Takeuchi, Yoshito,Nomura, Yujiro
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p. 871 - 872
(2007/10/02)
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- Ion Radicals. 46. Reactions of the Adducts of Thianthrene and Phenoxathiin Cation Radicals and Cyclohexene with Nucleophiles
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Thianthrene cation radical perchlorate 1a reacts with cyclohexene to give an adduct .Reactions of 2a with CN-, C6H5S-, and I- have been studied in dimethyl sulfoxide (Me2SO) and ethanol at room temperature.Reaction of the analogous adduct of cyclohexene and phenoxathiin cation radical perchlorate 2b with I- in ethanol was also studied.The reactions indicate that the adducts have the trans-1,2 structure and undergo facile substitution (SN2) and subsequent elimination (E2) reactions at room temperature.
- Iwai, Kiyoshi,Shine, Henry J.
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p. 271 - 276
(2007/10/02)
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- Novel cyano compounds
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A novel conjugated diene bisfunctionalization process wherein a nitro group and a hydroxyl group in the form of an ester are introduced into the conjugated diene molecule by treatment of conjugated dienes with nitric acid in the presence of an acid anhydride. The novel compounds produced by this process and transformation products thereof, are useful as bactericides and fungicides and valuable organic synthesis intermediates, A novel procedure for the production of nitriles and γ-acetoxytiglic aldehyde is disclosed.
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