- Unified Approach to Furan Natural Products via Phosphine-Palladium Catalysis
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Polyalkyl furans are widespread in nature, often performing important biological roles. Despite a plethora of methods for the synthesis of tetrasubstituted furans, the construction of tetraalkyl furans remains non-trivial. The prevalence of alkyl groups in bioactive furan natural products, combined with the desirable bioactivities of tetraalkyl furans, calls for a general synthetic protocol for polyalkyl furans. This paper describes a Michael–Heck approach, using sequential phosphine-palladium catalysis, for the preparation of various polyalkyl furans from readily available precursors. The versatility of this method is illustrated by the total syntheses of nine distinct polyalkylated furan natural products belonging to different classes, namely the furanoterpenes rosefuran, sesquirosefuran, and mikanifuran; the marine natural products plakorsins A, B, and D and plakorsin D methyl ester; and the furan fatty acids 3D5 and hydromumiamicin.
- Chen, Violet Yijang,Kwon, Ohyun
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supporting information
p. 8874 - 8881
(2021/03/17)
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- Enantioselective Nickel-Catalyzed Alkyne-Azide Cycloaddition by Dynamic Kinetic Resolution
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The triazole heterocycle has been widely adopted as an isostere for the amide bond. Many native amides are α-chiral, being derived from amino acids. This makes α-N-chiral triazoles attractive building blocks. This report describes the first enantioselective triazole synthesis that proceeds via nickel-catalyzed alkyne-azide cycloaddition (NiAAC). This dynamic kinetic resolution is enabled by a spontaneous [3,3]-sigmatropic rearrangement of the allylic azide. The 1,4,5-trisubstituted triazole products, derived from internal alkynes, are complementary to those commonly obtained by the related CuAAC reaction. Initial mechanistic experiments indicate that the NiAAC reaction proceeds through a monometallic Ni complex, which is distinct from the CuAAC manifold.
- Liu, En-Chih,Topczewski, Joseph J.
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supporting information
p. 5308 - 5313
(2021/05/04)
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- Copper-Catalyzed Cross-Nucleophile Coupling of β-Allenyl Silanes with Tertiary C-H Bonds: A Radical Approach to Branched 1,3-Dienes
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Described herein is a distinctive approach to branched 1,3-dienes through oxidative coupling of two nucleophilic substrates, β-allenyl silanes, and hydrocarbons appending latent functionality by copper catalysis. Notably, C(sp3)-H dienylation proceeded in a regiospecific manner, even in the presence of competitive C-H bonds that are capable of occurring hydrogen atom transfer process, such as those located at benzylic and other tertiary sites, or adjacent to an oxygen atom. Control experiments support the intermediacy of functionalized alkyl radicals.
- Shan, Qi-Chao,Hu, Lu-Min,Qin, Wei,Hu, Xu-Hong
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supporting information
p. 6041 - 6045
(2021/08/03)
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- 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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- 3-aryl-2-propyn-1-ol derivative and preparation method thereof
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The invention discloses a 3-aryl-2-propyn-1-ol derivative and a preparation method thereof, belongs to the field of organic synthesis, and particularly relates to a 3-aryl-2-propyn-1-ol derivative anda preparation method thereof. A purpose of the invention is to solve the problems of high energy consumption, high cost and environmental pollution caused by conditions of high temperature, metal catalysis, strong base or low temperature and the like required by the synthesis of the existing 3-aryl-2-propyn-1-ol derivative. The structural formula of the 3-aryl-2-propyn-1-ol derivative is shown inthe specification. The method comprises the following steps: 1, sequentially adding an aryl acetylene compound, an ammonium salt, an alkali, water and an organic solvent into a three-necked flask, and electrolyzing at room temperature in an air atmosphere under a stirring condition; 2, extracting, and carrying out reduced pressure distillation to remove the solvent to obtain a crude product; and3, purifying the crude product through silica gel column chromatography to obtain the 3-aryl-2-propyn-1-ol derivative. According to the invention, the 3-aryl-2-propyn-1-ol derivative can be obtained.
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Paragraph 0039-0054
(2020/12/31)
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- Bi(OTf)3 catalyzed synthesis of acyclic β-sulfanyl ketones via a tandem Meyer-Schuster rearrangement/conjugate addition reaction
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A new strategy to prepare acyclic β-carbonyl thioethers from propargyl alcohols and sulfur nucleophiles is reported. The investigation of the reaction substrates scope indicated that primary 3-aryl propargyl alcohols and thiols underwent the transformation smoothly. The reaction probably proceeded a Bi(OTf)3-catalyzed tandem Meyer-Schuster rearrangement of 3-aryl propargyl alcohol, followed by a thiol Michael conjugate addition of thiols to in situ generated α, β-unsaturated ketones. The method was 100% atom economic, high-yielding, and easy to handle, making it a valuable method for the construction of β-carbonyl sulfides.
- Wang, Yuan,Yin, Yan,Zhang, Qinglin,Pan, Wanyong,Guo, Huifeng,Pei, Keke
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supporting information
p. 2030 - 2034
(2019/07/03)
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- Iron-Catalyzed Coupling of Propargyl Bromides and Alkyl Grignard Reagents
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An iron-catalyzed Kumada-type cross-coupling reaction of propargyl halides with alkylmagnesium reagents is described. The reaction is fast, takes place in smooth conditions, tolerates several functional groups that would be able to react with the Grignard reagent, and may afford either allene or propargyl coupling derivatives. Factors involved in the observed regioselectivity have been studied.
- Domingo-Legarda, Pablo,Soler-Yanes, Rita,Quirós-López, M. Teresa,Bu?uel, Elena,Cárdenas, Diego J.
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supporting information
p. 4900 - 4904
(2018/09/10)
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- Fe(OTf)3-catalyzed tandem Meyer-Schuster rearrangement/intermolecular hydroamination of 3-aryl propargyl alcohols for the synthesis of acyclic β-Aminoketones
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Fe(OTf)3-catalyzed synthesis of acyclic β-aminoketones from 3-aryl propargyl alcohols and nitrogen nucleophiles were investigated. Results showed that propargyl alcohols without bulky groups α to the hydroxyl group underwent the transformation smoothly. Sulphonamides exhibited the higher reactivity than amides as the nitrogen nucleophiles and the transformation of acyclic β-aminoketones were finished in shorter reaction time and higher yields. Finally, racemic fluoxetine was efficiently accessed with the present reaction as the first step. This novel synthesis of acyclic β-aminoketones probable proceeded a Fe(OTf)3-catalyzed Meyer-Schuster rearrangement of 3-aryl propargyl alcohols, followed by a intermolecular hydroamination between nitrogen nucleophiles and α, β-unsaturated ketones.
- Tao, Ruiheng,Yin, Yan,Duan, Yongbin,Sun, Yuxing,Sun, Yue,Cheng, Fengkai,Pan, Jinpeng,Lu, Cheng,Wang, Yuan
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p. 1762 - 1768
(2017/03/08)
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- Structure-Based Design and Discovery of New M2 Receptor Agonists
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Muscarinic receptor agonists are characterized by apparently strict restraints on their tertiary or quaternary amine and their distance to an ester or related center. On the basis of the active state crystal structure of the muscarinic M2 receptor in complex with iperoxo, we explored potential agonists that lacked the highly conserved functionalities of previously known ligands. Using structure-guided pharmacophore design followed by docking, we found two agonists (compounds 3 and 17), out of 19 docked and synthesized compounds, that fit the receptor well and were predicted to form a hydrogen-bond conserved among known agonists. Structural optimization led to compound 28, which was 4-fold more potent than its parent 3. Fortified by the discovery of this new scaffold, we sought a broader range of chemotypes by docking 2.2 million fragments, which revealed another three micromolar agonists unrelated either to 28 or known muscarinics. Even pockets as tightly defined and as deeply studied as that of the muscarinic reveal opportunities for the structure-based design and the discovery of new chemotypes.
- Fish, Inbar,St??el, Anne,Eitel, Katrin,Valant, Celine,Albold, Sabine,Huebner, Harald,M?ller, Dorothee,Clark, Mary J.,Sunahara, Roger K.,Christopoulos, Arthur,Shoichet, Brian K.,Gmeiner, Peter
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supporting information
p. 9239 - 9250
(2017/11/30)
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- Enantioselective Formation of CF3-Bearing All-Carbon Quaternary Stereocenters via C-H Functionalization of Methanol: Iridium Catalyzed Allene Hydrohydroxymethylation
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Using an iridium catalyst modified by PhanePhos, CF3-allenes react with methanol to form branched products of hydrohydroxymethylation as single regioisomers with excellent levels of enantiomeric enrichment. This hydrogen autotransfer process enables catalytic enantioselective formation of acyclic CF3-bearing all-carbon quaternary stereocenters in the absence of stoichiometric metals or byproducts.
- Holmes, Michael,Nguyen, Khoa D.,Schwartz, Leyah A.,Luong, Tom,Krische, Michael J.
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supporting information
p. 8114 - 8117
(2017/06/28)
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- Cobalt-catalyzed (Z)-selective semihydrogenation of alkynes with molecular hydrogen
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Cobalt-catalyzed highly (Z)-selective semihydrogenation of alkynes using molecular H2 was developed using commercially available and cheap cobalt precursors. A variety of (Z)-alkenes were obtained in moderate to excellent selectivities [(Z)-alkene/(E)-alkene/alkane ratio up to >99 : 1 : 1] and it was found that the readily available ethylenediamine ligand is crucial in determining the selectivity.
- Chen, Caiyou,Huang, Yi,Zhang, Zongpeng,Dong, Xiu-Qin,Zhang, Xumu
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supporting information
p. 4612 - 4615
(2017/04/28)
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- Design and synthesis of novel xanthine derivatives as potent and selective A2B adenosine receptor antagonists for the treatment of chronic inflammatory airway diseases
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Adenosine induces bronchial hyperresponsiveness and inflammation in asthmatics through activation of A2B adenosine receptor (A2BAdoR). Selective antagonists have been shown to attenuate airway reactivity and improve inflammatory cond
- Basu, Sujay,Barawkar, Dinesh A.,Ramdas, Vidya,Patel, Meena,Waman, Yogesh,Panmand, Anil,Kumar, Santosh,Thorat, Sachin,Naykodi, Minakshi,Goswami, Arnab,Reddy, B. Srinivasa,Prasad, Vandna,Chaturvedi, Sandhya,Quraishi, Azfar,Menon, Suraj,Paliwal, Shalini,Kulkarni, Abhay,Karande, Vikas,Ghosh, Indraneel,Mustafa, Syed,De, Siddhartha,Jain, Vaibhav,Banerjee, Ena Ray,Rouduri, Sreekanth R.,Palle, Venkata P.,Chugh, Anita,Mookhtiar, Kasim A.
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p. 218 - 229
(2017/04/19)
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- Regioselective iodoazidation of alkynes: Synthesis of α,α-diazidoketones
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Aryl alkyl alkynes reacted with N-iodosuccinimide (NIS) and trimethylsilyl azide (TMSN3), leading to α,α-diazidoketones via the regioselective addition of IN3 to alkynes. Huisgen cyclization of α,α-diazidoketones generated bis-triazo
- Okamoto, Noriko,Sueda, Takuya,Minami, Hideki,Miwa, Yoshihisa,Yanada, Reiko
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supporting information
p. 1336 - 1339
(2015/03/14)
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- Zinc-catalyzed [4+3] cycloaddition with concomitant furan annulation: Formation of cyclohepta[b]furans
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A convenient zinc-promoted [4+3] cycloaddition of a carbonyl ene-yne with simple dienes was first achieved. This reaction provided an efficient strategy to prepare various cyclohepta[b]furan rings by cascade cycloadditions. Additionally, a multicomponent reaction of dione, alkynal, and diene was also reported, which exhibited a novel strategy for selective creations of C-O bonds and C-C bonds. Go tandem! A first zinc-catalyzed tandem [4+3] cycloaddition is presented herein. Various substituted cyclohepta[b]furans were synthesized from carbonyl ene-yne and diene in moderate to good yield. Furan rings and seven-membered rings were prepared in one single step (see scheme; TBS=tert-butyldimethyl).
- Song, Bo,Li, Lian-Hua,Song, Xian-Rong,Qiu, Yi-Feng,Zhong, Mei-Jin,Zhou, Ping-Xin,Liang, Yong-Min
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supporting information
p. 5910 - 5913
(2014/05/20)
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- Bi(OTf)3-catalyzed tandem Meyer-Schuster rearrangement and 1,4-addition to the resulting vinyl ketone
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Bi(OTf)3-catalyzed Meyer-Schuster rearrangement of electron-rich propargyl alcohols, followed by 1,4-addition of the resulting vinyl ketone, proceeded smoothly though Meyer-Schuster rearrangement of primary propargyl alcohols is rare. This tandem reaction can be extended to an intramolecular version, featuring a one-pot dihydroquinolone synthesis. (Chemical Equation Presented).
- Okamoto, Noriko,Sueda, Takuya,Yanada, Reiko
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p. 9854 - 9859
(2015/01/16)
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- Synthesis of molecular frameworks containing two distinct heterocycles connected in a single molecule with enhanced three-dimensional shape diversity
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Herein, we report the synthesis of fused-triazole scaffolds that are connected by pyrimidines, pyrazoles, or pyrazolopyrimidines through carbohydrate-derived stereodivergent linkers. Pyrimidine-, pyrazole-, or pyrazolopyrimidine-based carbohybrids were co
- Lim, Donghyun,Park, Seung Bum
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supporting information
p. 7100 - 7108
(2013/06/27)
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- 3,5-Disubstituted 6H-pyrrolo[1,2-c][1,2,3]triazoles from Morita-Baylis-Hillman adducts of propargyl aldehydes
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A simple method for synthesizing several 6H-pyrrolo[1,2-c][1,2,3]triazole derivatives having a methoxycarbonyl or an acetyl group at C-5 position and 7,8-dihydro-4H-[1,2,3]triazolo[1,5-a]indol-5(6H)-ones via an intramolecular 1,3-dipolar cycloaddition reaction of azido enynes, which were readily obtained from the Morita-Baylis-Hillman acetates of propargyl aldehydes with sodium azide, has been developed.
- Park, Sun Pil,Ahn, Sang-Hyun,Lee, Kee-Jung
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experimental part
p. 3490 - 3498
(2010/06/17)
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- Sonogashira cross-coupling using carbon aerogel doped with palladium nanoparticles; a recoverable and reusable catalyst
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The Sonogashira cross coupling of aryl iodides with terminal alkynes has been carried out in the presence of carbon aerogels doped with metallic palladium nanoparticles. Coupling products have been isolated in excellent yields and the catalyst system can
- Soler, Roger,Cacchi, Sandro,Fabrizi, Giancarlo,Forte, Giovanni,Martin, Laura,Martinez, Sandra,Molins, Elies,Moreno-Manas, Marcial,Petrucci, Francesco,Roig, Anna,Sebastian, Rosa M.,Vallribera, Adelina
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p. 3068 - 3072
(2008/03/14)
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- Formate as a CO surrogate for cascade processes: Rh-catalyzed cooperative decarbonylation and asymmetric Pauson-Khand-type cyclization reactions
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A rhodium-(S)-xyl-BINAP complex-catalyzed tandem formate decarbonylation and [2 + 2 + 1] carbonylative cyclization is described; this cooperative process utilizes formate as a condensed CO source, and the newly developed cascade protocol can be extended t
- Lee, Hang Wai,Chan, Albert S. C.,Kwong, Fuk Yee
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p. 2633 - 2635
(2008/02/08)
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- Iridium-catalyzed cascade decarbonylation/highly enantioselective Pauson-Khand-type cyclization reactions
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An easily accessible chiral iridium-BINAP complex can effect the cooperative processes of decarbonylation of an aldehyde and cascaded enantioselective Pauson-Khand-type reaction. A survey of ligands revealed that atropisomeric aryl-diphosphine ligands wer
- Kwong, Fuk Yee,Lee, Hang Wai,Lam, Wai Har,Qiu, Liqin,Chan, Albert S.C.
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p. 1238 - 1252
(2007/10/03)
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- Synthesis of 3-substituted furans by hydroformylation
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A simple and novel method for the synthesis of 3-substituted furans by the hydroformylation of substituted propargylic alcohols is described using rhodium acetate and triphenylphosphine in dichloromethane. The hydroformylation reaction proceeds in a regio
- Nanayakkara, Peru,Alper, Howard
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p. 545 - 550
(2007/10/03)
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- Rhodium-bisbenzodioxanphos complex-catalyzed homogeneous enantioselective Pauson-Khand-type cyclization in alcoholic solvents
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The chiral atropisomeric diphosphane ligand (S)-BisbenzodioxanPhos was found to be highly effective in the co-operative processeses of aldehyde decarbonylation and cascaded enantioselective Pauson-Khand-type reactions. Various 1,6-enynes were transformed
- Fuk, Yee Kwong,Hang, Wai Lee,Qiu, Liqin,Wai, Har Lam,Li, Yue-Ming,Hoi, Lun Kwong,Chan, Albert S. C.
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p. 1750 - 1754
(2007/10/03)
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- Rhodium-catalyzed asymmetric aqueous Pauson-Khand-type reaction
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An interesting rhodium-catalyzed asymmetric aqueous Pauson-Khand-type reaction was developed. A chiral atropisomeric dipyridyldiphosphane ligand was found to be highly effective in this system. This operationally simple protocol allows both catalyst and r
- Kwong, Fuk Yee,Li, Yue Ming,Lam, Wai Har,Qiu, Liqin,Lee, Hang Wai,Yeung, Chi Hung,Chan, Kin Shing,Chan, Albert S. C.
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p. 3872 - 3880
(2007/10/03)
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- Design and synthesis of m1-selective muscarinic agonists: (R)-(-)-(Z)- 1-azabicyclo[2.2.1]heptan-3-one, O-(3-(3'-methoxyphenyl)-2-propynyl)-oxime maleate (CI-1017), a functionally m1-selective muscarinic agonist
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The synthesis and SAR of a series of (Z)-(±)-1- azabicyclo[2.2.1]heptan-3-one, O-(3-aryl-2-propynyl)oximes are described. The biochemistry and pharmacology of 24Z (PD 142505) and its enantiomers are highlighted. 24Z is functionally an m1-selective muscari
- Tecle, Halle,Barrett, Stephen D.,Lauffer, David J.,Augelli-Szafran, Corinne,Brann, Mark R.,Callahan, Michael J.,Caprathe, Bradley W.,Davis, Robert E.,Doyle, Patricia D.,Eubanks, David,Lipiniski, William,Mirzadegan, Tara,Moos, Walter H.,Moreland,Nelson, Carrie B.,Pavia, Michael R.,Raby, Charlotte,Schwarz, Roy D.,Spencer, Carolyn J.,Thomas, Anthony J.,Jaen, Juan C.
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p. 2524 - 2536
(2007/10/03)
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- Synthesis and Electrochemical Properties of 4-Phenyl-1-buten-3-yne-1,1,2-tricarbonitriles and Tricyanoacrylates
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The reaction of phenylacetylenes 4a-h copper(I) acetate (5) and TCNE (tetracyanoethylene) in THF/acetonitrile gave 4-phenyl-1-buten-3-yne-1,1,2-tricarbonitriles 6a-h. 4i did not react to give 6i.The phenylacetylenes 4b-i were prepared by a two-step synthesis starting from the corresponding phenyl halides 1b-i.The tricyanoacrylates 8 were synthesised from the corresponding cyanoacetates 7, TCNE and catalytic amounts of pyridine in THF. - Cyclovoltammetric investigations showed that the butenynes 6 and the tricyanoacrylates 8 are strong electron acceptors which can be easily reduced.The radical anions 6.- are unstable in acetonitrile and react irreversibly with 6 to give oligomeric anions 6.-n.Only 4-(2,4,6-trimethoxyphenyl)-1-buten-3-yne-1,1,2-tricarbonitrile (6h) is reduced to a radical anion 6h.- which associates with 6h in a reversible follow-up process to form a dimeric anion 6h2.-.By contrast, the tricyanoacrylates 8 can be reversibly reduced to their respective radical anions and dianions. - Keywords: Cyano compounds, conjugated / Phenylacetylenes / Radical anions / Electrochemistry
- Dulog, Lothar,Koerner, Bernd,Heinze, Juergen,Yang, Jianjun
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p. 1663 - 1672
(2007/10/02)
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