- Palladium-Catalyzed Synthesis of Tricyclic Indoles via a N-S Bond Cleavage Strategy
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In palladium/norbornene (Pd/NBE) chemistry, the "ortho effect"has been proven to be a key factor in the process of β-carbon elimination to extrude NBE. Herein, we found that the o-iodoaniline protected by a p-methoxybenzenesulfonyl group can recover the "
- Zhang, Bo-Sheng,Wang, Fan,Gou, Xue-Ya,Yang, Ying-Hui,Jia, Wan-Yuan,Liang, Yong-Min,Wang, Xi-Cun,Li, Yuke,Quan, Zheng-Jun
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supporting information
p. 7518 - 7523
(2021/10/01)
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- Ruthenium-catalyzed cascade C-H activation/annulation of: N -alkoxybenzamides: Reaction development and mechanistic insight
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A highly selective ruthenium-catalyzed C-H activation/annulation of alkyne-tethered N-alkoxybenzamides has been developed. In this reaction, diverse products from inverse annulation can be obtained in moderate to good yields with high functional group compatibility. Insightful experimental and theoretical studies indicate that the reaction to the inverse annulation follows the Ru(ii)-Ru(iv)-Ru(ii) pathway involving N-O bond cleavage prior to alkyne insertion. This is highly different compared to the conventional mechanism of transition metal-catalyzed C-H activation/annulation with alkynes, involving alkyne insertion prior to N-O bond cleavage. Via this pathway, the in situ generated acetic acid from the N-H/C-H activation step facilitates the N-O bond cleavage to give the Ru-nitrene species. Besides the conventional mechanism forming the products via standard annulation, an alternative and novel Ru(ii)-Ru(iv)-Ru(ii) mechanism featuring N-O cleavage preceding alkyne insertion has been proposed, affording a new understanding of transition metal-catalyzed C-H activation/annulation.
- Harvey, Jeremy N.,Song, Liangliang,Tang, Xiao,Van Der Eycken, Erik V.,Van Der Eycken, Johan,Van Meervelt, Luc,Zhang, Xiaoyong
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p. 11562 - 11569
(2020/11/23)
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- Nickel-Catalyzed Formal Aminocarbonylation of Unactivated Alkyl Iodides with Isocyanides
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Herein, we disclose a Ni-catalyzed formal aminocarbonylation of primary and secondary unactivated aliphatic iodides with isocyanides to afford alkyl amide, which proceeds via the selective monomigratory insertion of isocyanides with alkyl iodides, subsequent β-hydride elimination, and hydrolysis process. The reaction features wide functional group tolerance under mild conditions. Additionally, the selective, one-pot hydrolysis of reaction mixture under acid conditions allows for expedient synthesis of the corresponding alkyl carboxylic acid.
- Chen, Yifeng,Huang, Wenyi,Qu, Jingping,Shrestha, Mohini,Wang, Yun,Weng, Yangyang
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supporting information
p. 3245 - 3250
(2020/04/21)
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- Gold-Catalyzed Hydrofluorination of Internal Alkynes Using Aqueous HF
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The gold-catalyzed hydrofluorination reaction of internal alkynes using hydrofluoric acid is reported. Notably, those conditions use one of the most economical sources of HF and are free of additional additives. Both symmetrical and unsymmetrical internal alkynes can be utilized, and the use of alkynes bearing a fluorinated group at the propargylic position as substrates allowed for a regioselective hydrofluorination reaction.
- Gauthier, Rapha?l,Mamone, Marius,Paquin, Jean-Fran?ois
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supporting information
p. 9024 - 9027
(2019/11/14)
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- Regioselectivity Influences in Platinum-Catalyzed Intramolecular Alkyne O-H and N-H Additions
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The steric and electronic drivers of regioselectivity in platinum-catalyzed intramolecular hydroalkoxylation are elucidated. A branch point is found that divides the process between 5-exo and 6-endo selective processes, and enol ethers can be accessed in good yields for both oxygen heterocycles. The main influence arises from an electronic effect, where the alkyne substituent induces a polarization of the alkyne that leads to preferential heteroatom attack at the more electron-deficient carbon. The electronic effects are studied in other contexts, including hydroacyloxylation and hydroamination, and similar trends in directionality are predominant although not uniformly observed.
- Costello, Jeff P.,Ferreira, Eric M.
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supporting information
p. 9934 - 9939
(2019/12/24)
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- Ni-Catalyzed Cyclization of Enynes and Alkynylboronates: Atom-Economical Synthesis of Boryl-1,4-dienes
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We report a novel atom-economical Ni-catalyzed cyclization reaction of enynes with alkynylboronates. The reaction employs a non-expensive Ni salt, a phosphine-based ligand and easy-handling alkynylboronates as boron–carbon source. The reaction provides co
- Cabrera-Lobera, Natalia,Quirós, M. Teresa,Bu?uel, Elena,Cárdenas, Diego J.
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supporting information
p. 14512 - 14516
(2019/11/11)
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- Synthesis of Primitive Dendrimer Systems Bearing Bicyclo[3,2,0]Hept-6-en-6-yl Groups via Unique Au-catalyzed [2+2] Cyclization
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Propargylic pivaloates bearing an alkynyl group at a three-carbon tether under the gold catalysis would undergo [3,3] rearrangements of propargylic pivaloates followed by tandem [2+2] cyclization to give the corresponding 6-acylbicyclo[3,2,0]hept-6-ens. In continuing work, we prepared various substrates bearing two arms of alkyne-propargylic pivaloates to explore primitive dendrimer concept bicyclic compounds. Finally, we could obtain a series of diasteromeric compounds bearing two arms of 6-acylbicyclo[3,2,0]hept-6-ene groups in high yields.
- Lee, Kyu Hwan,Jillella, Raveendra,Kim, Jaewoong,Oh, Chang Ho
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supporting information
p. 651 - 656
(2018/04/30)
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- Titanium-Promoted Cross-Coupling for the Selective Synthesis of Polysubstituted, Conjugated Amides
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α,β-Unsaturated amides are important building blocks and are key structural elements in a number of biologically active natural products. Despite their importance and prevalence, few methods exist to prepare conjugated amides directly and modularly. To address this gap, a titanium-promoted coupling of alkynes and isocyanates has been developed. The method is highly stereoselective, producing only the E isomer with good chemoselectivity and regioselectivity (>95/5), for unsymmetrical internal alkynes that contain a steric bias. The reactive titanacyclopentene intermediate formed from the coupling of the alkyne and isocyanate was additionally reacted with various electrophiles to access tetrasubstituted enamides.
- Chenniappan, Vinoth Kumar,Rahaim, Ronald J.
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supporting information
p. 5090 - 5093
(2016/10/14)
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- Ni-Catalyzed Carboxylation of Unactivated Alkyl Chlorides with CO2
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A catalytic carboxylation of unactivated primary, secondary, and tertiary alkyl chlorides with CO2 at atmospheric pressure is described. This protocol represents the first intermolecular cross-electrophile coupling of unactivated alkyl chlorides, thus leading to new knowledge in the cross-coupling arena.
- B?rjesson, Marino,Moragas, Toni,Martin, Ruben
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supporting information
p. 7504 - 7507
(2016/07/06)
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- Ethylene transposition: Ruthenium hydride catalyzed intramolecular trans -silylvinylation of internal alkynes
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A highly selective intramolecular trans-silylvinylation of internal alkynes catalyzed by RuHCl(CO)(SIMes)(PPh3) has been accomplished. The use of methyl vinyl ketone as an additive increased the efficiency of this transformation. This process w
- Liu, Shasha,Zhao, Jinbo,Kaminsky, Lauren,Wilson, Robert J.,Marino, Nadia,Clark, Daniel A.
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supporting information
p. 4456 - 4459
(2015/01/16)
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- The mechanism of gold(I)-catalyzed hydroalkoxylation of alkynes: An extensive experimental study
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An extensive experimental study of the mechanism of gold(I)-catalyzed hydroalkoxylation of internal alkynes has been conducted by using NMR spectroscopy. This study was focused on the organogold intermediates, observations of actual catalytic intermediates in situ, and the reaction kinetics that are involved in this reaction. Based on the experimental results, a complete mechanistic picture was established, including on- and off-cycle processes that explain the role of diaurated species. We have shown that gold-catalyzed hydroalkoxylation of internal alkynes is a reaction that requires only one gold atom for the catalytic cycle, disproving a recent hypothesis regarding the involvement of cooperative gold catalysis.
- Zhdanko, Alexander,Maier, Martin E.
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supporting information
p. 1918 - 1930
(2014/03/21)
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- Rh(III)-catalyzed intramolecular redox-neutral or oxidative cyclization of alkynes: Short, efficient synthesis of 3,4-fused indole skeletons
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A Rh(III)-catalyzed intramolecular redox-neutral or oxidative annulation of a tethered alkyne has been developed to efficiently construct 3,4-fused indoles via a C-H activation pathway. The advantages of this process are (1) ready availability of annulation precursors; (2) broad substrate scope; (3) complete regioselectivity; (4) simple and mild reaction conditions; and (5) no need for an external oxidant or to employ molecular oxygen as the stoichiometric terminal oxidant.
- Zhou, Bing,Yang, Yaxi,Tang, Huanyu,Du, Juanjuan,Feng, Huijin,Li, Yuanchao
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supporting information
p. 3900 - 3903
(2014/08/18)
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- Discovery, synthetic methodology, and biological evaluation for antiphotoaging activity of bicyclic[1,2,3]triazoles: In vitro and in vivo studies
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Novel bicyclic[1,2,3]triazoles (4, 7, 11, 15) have been synthesized using a one-pot metal free strategy with high structural diversity as photoprotective agents, and their effect on UVA-induced senescence in human dermal fibroblast cells (FB) and the asso
- Hsieh, Hsin-Yu,Lee, Wen-Chun,Senadi, Gopal Chandru,Hu, Wan-Ping,Liang, Jium-Jia,Tsai, Tong-Rong,Chou, Yu-Wei,Kuo, Kung-Kai,Chen, Chung-Yu,Wang, Jeh-Jeng
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supporting information
p. 5422 - 5435
(2013/07/26)
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- Copper-free sonogashira coupling reaction using a trans-spanning 1,2-Bis(2-thienylethynyl)benzene Ligand
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Novel copper-free Sonogashira coupling reaction of aryl halides with terminal acetylenes proceeded in the presence of 1,2-bis(2-thienylethynyl) benzene (1) as a trans-bidentatable ligand.
- Atobe, Shingo,Sonoda, Motohiro,Suzuki, Yuki,Shinohara, Hiroyuki,Yamamoto, Takuya,Ogawa, Akiya
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supporting information; experimental part
p. 925 - 927
(2011/12/05)
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- Step-economical synthesis of taxol-like tricycles through a palladium-catalyzed domino reaction
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A quick and easy way to produce tricycles related to the core structure of taxanes has been achieved using a palladium-catalyzed domino reaction (see scheme, Bz=benzoyl). These studies have been performed with function-oriented synthesis in mind. An effic
- Petrignet, Julien,Boudhar, Aicha,Blond, Gaelle,Suffert, Jean
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supporting information; experimental part
p. 3285 - 3289
(2011/05/16)
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- An alternative approach to aldol reactions: Gold-catalyzed formation of boron enolates from alkynes
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A new method for enolate generation via the gold-catalyzed addition of boronic acids to alkynes is reported. The formation of boron enolates from readily accessible ortho-alkynylbenzeneboronic acids proceeds rapidly with 2 mol % PPh3AuNTf2
- Koerner, Cindy,Starkov, Pavel,Sheppard, Tom D.
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supporting information; experimental part
p. 5968 - 5969
(2010/07/05)
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- The acid-mediated intramolecular 1,3-dipolar cycloaddition of derived 2-nitro-1,1-ethenediamines for the synthesis of novel fused bicyclic isoxazoles
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The discovery of a novel synthesis of new fused bicyclic isoxazoles, for example, N-methyl-3-phenyl-5,6-dihydro-4H-isoxazolo[3,4-c]azepin-8-amine (2a), N-methyl-3-phenyl-4,5-dihydroisoxazolo[3,4-c]pyridin-7-amine (2b) and N-methyl-3-phenyl-4H-pyrrolo[3,4-
- Page, Lee W.,Bailey, Matthew,Beswick, Paul J.,Frydrych, Simon,Gleave, Robert J.
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scheme or table
p. 3388 - 3391
(2010/09/05)
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- Indium(III)-catalyzed coupling between alkynes and aldehydes to α,β-unsaturated ketones
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The combined use of a catalytic amount of InX3 (X = OTf and NTf2) and 1-butanol was found to be effective in formal alkynealdehyde metathesis. With this catalytic system, aromatic alkynes reacted with aromatic aldehydes to give chalcones in moderate to good yields. Alkynals were efficiently converted into 5- to 7-membered cyclic compounds by intramolecular alkyne-aldehyde coupling.
- Miura, Katsukiyo,Yamamoto, Kiyomi,Yamanobe, Aya,Ito, Keisuke,Kinoshita, Hidenori,Ichikawa, Junji,Hosomi, Akira
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supporting information; experimental part
p. 766 - 767
(2011/01/09)
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- Synthesis of pyridines and pyrazines using an intramolecular hydroamination-based reaction sequence
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A management issue! Various pyridines and pyrazines can be efficiently accessed from simple acyclic precursors using an intramolecular hydroamination/isomerization/aromatization sequence (see scheme). ρ-Toluenesulfonic acid (2 mol%) is used to catalyze this novel alkyne annulation, in which the oxime group allows for a subsequent redoxneutral aromatization step to occur.
- Rizk, Toni,Bilodeau, Eric J.-F.,Beauchemin, Andre M.
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supporting information; experimental part
p. 8325 - 8327
(2010/01/16)
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- Gold-catalyzed synthesis of bicyclo[4.3.0]nonadiene derivatives via tandem 6-endo-dig/Nazarov cyclization of 1,6-allenynes
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(Chemical Equation Presented) Catalytic cyclization of 1,6-allenynes was achieved by AuPPh3SbF6 (5 mol %) in cold CH 2Cl2 (0°C, 0.5-4 h) to form bicyclo[4.3.0]nonadiene products; this cyclization proceeded more
- Lin, Guan-You,Yang, Chun-Yao,Liu, Rai-Shung
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p. 6753 - 6757
(2008/02/10)
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- Constrained geometry organoactinides as versatile catalysts for the intramolecular hydroamination/cyclization of primary and secondary amines having diverse tethered C-C unsaturation
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A series of "constrained geometry" organoactinide complexes, (CGC)An(NMe)2 (CGC = Me2-Si(η5-Me 4C5)(tBuN); An = Th, 1; U, 2), has been prepared via efficient in situ, two-step protodeamination routes in good yields and high purity. Both 1 and 2 are quantitatively converted to the neutrally charged, solvent-free dichlorides (1-Cl2, 2-Cl2) and slightly more soluble diiodides (1-I2, 2-I2) with excess Me3Si-X (X = Cl, I) in non-coordinating solvents. The new complexes were characterized by NMR spectroscopy, elemental analysis, and (for 1 and 2) single-crystal X-ray diffraction, revealing substantially increased metal coordinative unsaturation vs the corresponding Me2SiCp″ 2AnR2 (Cp″ = η5-Me4C 5; An = Th, R = CH2-(SiMe3), 3; An = U, R = CH2Ph, 4) and Cp′2AnR2 (Cp′ = η5-Me5C5 ; An = Th, R = CH 2(SiMe3), 5; An = U, R = CH2(SiMe3), 6) complexes. Complexes 1-6 exhibit broad applicability for the intramolecular hydroamination of diverse C-C unsaturations, including terminal and internal aminoalkenes (primary and secondary amines), aminoalkynes (primary and secondary amines), aminoallenes, and aminodienes. Large turnover frequencies (N t up to 3000 h-1) and high regioselectivities (≥95%) are observed throughout, along with moderate to high diastereoselectivities (up to 90% trans ring closures). With several noteworthy exceptions, reactivity trends track relative 5f ionic radii and ancillary ligand coordinative unsaturation. Reactivity patterns and activation parameters are consistent with a reaction pathway proceeding via turnover-limiting C=C/C=C insertion into the An-N σ-bond.
- Stubbert, Bryan D.,Marks, Tobin J.
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p. 4253 - 4271
(2008/02/01)
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- The Photo-Dehydro-Diels-Alder (PDDA) reaction - A powerful method for the preparation of biaryls
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The photochemically initiated dehydro-Diels-Alder (PDDA) reaction is an efficient and versatile method for the preparation of biaryls. The ring closure may take place both inter- and intramolecularly, of which the intramolecular variant is more productive
- Wessig, Pablo,Mueller, Gunnar,Pick, Charlotte,Matthes, Annika
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p. 464 - 477
(2007/12/27)
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- Palladium-catalyzed intramolecular asymmetric hydroamination, hydroalkoxylation, and hydrocarbonation of alkynes
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A conceptually novel approach for asymmetric intramolecular hydroamination, hydroalkoxylation and hydrocarbonation of alkynes using chiral palladium catalysts are described. The reactions of the aminoalkynes 5, alkynols 7, and alkynylmethines 9 in the pre
- Patil, Nitin T.,Lutete, Leopold Mpaka,Wu, Huanyou,Pahadi, Nirmal K.,Gridnev, Ilya D.,Yamamoto, Yoshinori
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p. 4270 - 4279
(2007/10/03)
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- Tandem nucleophilic addition/fragmentation reactions and synthetic versatility of vinylogous acyl triflates
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A thorough analysis of the chemistry of vinylogous acyl triflates provides insight into important chemical processes and opens new directions in synthetic technology. Tandem nucleophilic addition/C-C bond cleaving fragmentation reactions of cyclic vinylogous acyl triflates 1 yield a variety of acyclic acetylenic compounds. Full details are disclosed herein. A wide array of nucleophiles, such as organolithium and Grignard reagents, lithium enolates and their analogues, hydride reagents, and lithium amides, are applied. The respective reactions produce ketones 2, 1,3-diketones and their analogues 3, alcohols 4, and amides 5. The present reactions are proposed to proceed through a 1,2-addition of the nucleophile to the carbonyl group of starting triflates 1 to form tetrahedral alkoxide intermediates C, followed by Grob-type fragmentation, which effects C-C bond cleavage to yield acyclic acetylenic compounds 2-5 and 7. The potent nucleofugacity of the triflate moiety is channeled through the σ-bond framework of 1, providing direct access to the fragmentation pathway without denying other typical reactions of cyclic vinylogous esters. The synthetic versatility of vinylogous acyl triflates, including functionalization reactions of the cyclic enone core (1 → 6 or 8), is also illustrated.
- Kamijo, Shin,Dudley, Gregory B.
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p. 6499 - 6507
(2007/10/03)
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- Intramolecular hydroamination of alkynes catalyzed by Pd(PPh 3)4/triphenylphosphine under neutral conditions
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The intramolecular hydroamination of alkynes tethered with amino group 1 in the presence of catalytic amounts of Pd(PPh3)4 and PPh3 in benzene at 100°C proceeded smoothly without the use of any additional acid source to af
- Bajracharya, Gan B.,Huo, Zhibao,Yamamoto, Yoshinori
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p. 4883 - 4886
(2007/10/03)
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- Rh(I)-catalyzed CO gas-free cyclohydrocarbonylation of alkynes with formaldehyde to α,β-butenolides
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The rhodium(I)-catalyzed reaction of alkynes with formaldehyde proceeds via the double incorporation of a carbonyl moiety from formaldehyde, resulting in a CO gas-free cyclohydrocarbonylation leading to α,β-butenolides. The Royal Society of Chemistry 2005.
- Fuji, Koji,Morimoto, Tsumoru,Tsutsumi, Ken,Kakiuchi, Kiyomi
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p. 3295 - 3297
(2007/10/03)
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- Syntheses and mesomorphic and luminescent properties of disubstituted polyacetylenes bearing biphenyl pendants
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Liquid-crystalline and light-emitting poly(2-alkyne)s and poly(-phenyl-1-alkyne)s containing biphenyl (Biph) cores, alkyl spacers, and alkoxy tails (-{RC=C[(CH2)m-OCO-Biph-OC7H 15]}n-, where R, m = CH
- Dong, Yuping,Lam, Jacky W.Y.,Peng, Han,Cheuk, Kevin K.L.,Kwok, Hoi Sing,Tang, Ben Zhong
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p. 6408 - 6417
(2007/10/03)
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- Cascade Cyclizations and Couplings Involving Nickel Enolates
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A new strategy for effecting cascade cyclization processes using nickel enolates has been developed. Nickel enolates may be cleanly generated by the oxidative cyclization of an enal and alkyne with Ni(O), and the resulting enolate may be functionalized by a variety of alkylation processes. Partially and fully intramolecular versions of the process allow the rapid synthesis of complex polycyclics from simple achiral, acyclic precursors.
- Mahandru, Gireesh M.,Skauge, Andy R. L.,Chowdhury, Sanjoy K.,Amarasinghe, Kande K. D.,Heeg, Mary Jane,Montgomery, John
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p. 13481 - 13485
(2007/10/03)
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- Nickel-catalyzed reductive coupling of alkynes and epoxides
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Nickel-catalyzed, intramolecular and intermolecular reductive coupling of alkynes and epoxides affords synthetically useful homoallylic alcohols of defined alkene geometry. Very high regioselectivity is generally observed, and cyclizations proceed with complete selectivity for endo epoxide opening. This catalytic reaction represents the first use of a non-π-based electrophile in a growing class of nickel-catalyzed, multicomponent coupling reactions, and is the first catalytic method of reductive coupling of alkynes and epoxides that is effective for both intermolecular and intramolecular cases, and mechanistically distinct from these, possibly involving a nickella(II)oxetane. Copyright
- Molinaro, Carmela,Jamison, Timothy F.
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p. 8076 - 8077
(2007/10/03)
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- Synthesis of isoindolo[2,1-α]indoles by the palladium-catalyzed annulation of internal acetylenes
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A wide variety of substituted isoindolo[2,1-α]indoles have been prepared via annulation of internal alkynes by imines derived from o-iodoanilines in the presence of a palladium catalyst. This methodology provides an extremely efficient route for the synth
- Roesch,Larock
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p. 412 - 420
(2007/10/03)
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- An efficient palladium-catalysed coupling of terminal alkynes with aryl halides and Jeffery's conditions
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Palladium-catalysed coupling of terminal alkynes with aryl halides occurs at room temperature in quite good yields in the presence of quaternary ammonium salt and a base in a acetonitrile-water solution, without any added cuprous iodide.
- Nguefack, Jean-Flaubert,Bolitt, Veronique,Sinou, Denis
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p. 5527 - 5530
(2007/10/03)
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