- Electrochemical Ring-Opening Dicarboxylation of Strained Carbon-Carbon Single Bonds with CO2: Facile Synthesis of Diacids and Derivatization into Polyesters
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Diacids are important monomers in the polymer industry to construct valuable materials. Dicarboxylation of unsaturated bonds, such as alkenes and alkynes, with CO2 has been demonstrated as a promising synthetic method. However, dicarboxylation of C-C single bonds with CO2 has rarely been investigated. Herein we report a novel electrochemical ring-opening dicarboxylation of C-C single bonds in strained rings with CO2. Structurally diverse glutaric acid and adipic acid derivatives were synthesized from substituted cyclopropanes and cyclobutanes in moderate to high yields. In contrast to oxidative ring openings, this is also the first realization of an electroreductive ring-opening reaction of strained rings, including commercialized ones. Control experiments suggested that radical anions and carbanions might be the key intermediates in this reaction. Moreover, this process features high step and atom economy, mild reaction conditions (1 atm, room temperature), good chemoselectivity and functional group tolerance, low electrolyte concentration, and easy derivatization of the products. Furthermore, we conducted polymerization of the corresponding diesters with diols to obtain a potential UV-shielding material with a self-healing function and a fluorine-containing polyester, whose performance tests showed promising applications.
- Liao, Li-Li,Wang, Zhe-Hao,Cao, Ke-Gong,Sun, Guo-Quan,Zhang, Wei,Ran, Chuan-Kun,Li, Yiwen,Chen, Li,Cao, Guang-Mei,Yu, Da-Gang
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supporting information
p. 2062 - 2068
(2022/02/10)
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- Boronic Acid-Mediated Photocatalysis Enables the Intramolecular Hydroacylation of Olefins Using Carboxylic Acids
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An intramolecular hydroacylation of olefins using carboxylic acids (CAs) has been developed. With the aid of a boronic acid, CAs can be used as acyl-radical precursors in catalytic photoredox reactions driven by visible light. The CAs are easily converted into their corresponding cyclic ketones without the need to use any stoichiometric activating reagents. Mechanistic studies implied that the formation of an “ate” complex from the CA and boronic acid is crucial for the generation of the acyl radical equivalent from the unreactive carboxy group.
- Nanjo, Takeshi,Takemoto, Yoshiji,Yumura, Taichi
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supporting information
(2022/03/31)
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- Green Esterification of Carboxylic Acids Promoted by tert-Butyl Nitrite
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In this work, the green esterification of carboxylic acids promoted by tert-butyl nitrite has been well developed. This transformation is compatible with a broad range of substrates and exhibits excellent functional group tolerance. Various drugs and substituted amino acids are applicable to this reaction under near neutral conditions, with good to excellent yields.
- Cheng, Xionglve,Jiang, Gangzhong,Li, Xingxing,Tao, Suyan,Wan, Xiaobing,Zhao, Yanwei,Zheng, Yonggao
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supporting information
p. 2713 - 2718
(2021/06/25)
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- The Versatile Reaction Chemistry of an Alpha-Boryl Diazo Compound
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The first α-boryl diazo compound that is capable of engaging in classic synthetic organic diazo reaction chemistry is described. The diazomethyl-1,2-azaborine 1, which is a BN isostere of phenyldiazomethane, is significantly more stable than phenyldiazomethane; its reaction chemistry ranges from C-H activation, O-H activation, [3+2] cycloaddition, and halogenation, to Ru-catalyzed carbonyl olefination. The demonstrated broad range of reactivity of diazomethyl-1,2-azaborine 1 makes it an exceptionally versatile synthetic building block for the 1,2-azaborine heterocyclic motif.
- Cuenca, Ana Belén,Li, Bo,Liu, Shih-Yuan,Liu, Yao,Puig De La Bellacasa, Raimon
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supporting information
p. 14059 - 14064
(2021/09/15)
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- Facile synthesis of libraries of functionalized cyclopropanes and oxiranes using ionic liquids – A new approach to the classical Corey-Chaykovsky reaction
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The potential of [PAIM][NTf2]/BMIM-ILs as a base/solvent in the Corey-Chaykovsky reaction is demonstrated by the facile synthesis of libraries of functionalized cyclopropanes from enones and oxiranes from aldehydes and ketones, at room temperature in respectable isolated yields. To demonstrate their application, the synthesized epoxides were employed as substrates for the synthesis of a library of 2,3-disubstituted quinolines, using [BMIM(SO3H)][OTf]/[BMIM][PF6] as a catalyst/solvent. The potential for recycling/reuse of the IL solvents was also explored.
- Malunavar, Shruti S.,Sutar, Suraj M.,Prabhala, Pavankumar,Savanur, Hemantkumar M.,Kalkhambkar, Rajesh G.,Aridoss, Gopalakrishnan,Laali, Kenneth K.
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supporting information
(2021/09/13)
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- Donor-Acceptor Bicyclopropyls as 1,6-Zwitterionic Intermediates: Synthesis and Reactions with 4-Phenyl-1,2,4-triazoline-3,5-dione and Terminal Acetylenes
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The bicyclopropyl system activated by incorporation of donor and acceptor groups in the presence of Lewis acids was used as a synthetic equivalent of 1,6-zwitterions. Opening of both cyclopropane rings in 2′-aryl-1,1′-bicyclopropyl-2,2-dicarboxylates (D-A bicyclopropyl, ABCDs) in the presence of GaI3 + Bu4N+GaI4- results in 5-iodo-5-arylpent-2-enylmalonates as products of HI formal 1,6-addition to the bicyclopropyl system. The use of GaCl3 or GaBr3 as a Lewis acid and terminal aryl or alkyl acetylenes as 1,6-zwitterion interceptors allows the alkyl substituent to be grown to give the corresponding acyclic 7-chloro(bromo)-hepta-2,6-dienylmalonates. The reaction of ABCDs with 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) catalyzed by Yb(OTf)3 also results in the opening of both cyclopropane rings. The reaction products are tetrahydropyridazine derivatives - (7,9-dioxo-1,6,8-triazabicyclo[4.3.0]non-3-en-2-ylmethyl)malonates - containing one more PTAD moiety in the malonyl group.
- Potapov, Konstantin V.,Denisov, Dmitry A.,Glushkova, Valeriia V.,Novikov, Roman A.,Tomilov, Yury V.
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p. 15562 - 15576
(2020/11/30)
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- ARYL CYCLOPROPYL-AMINO-ISOQUINOLINYL AMIDE COMPOUNDS
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Provided herein are arylcyclopropyl amino-isoquinoline amide compounds. In particular, the disclosure provides compounds that affect the function of kinases in a cell and that are useful as therapeutic agents or with therapeutic agents. The compounds of t
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Page/Page column 110-111
(2018/10/25)
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- Catalytic Hydrogenolysis of Enantioenriched Donor–Acceptor Cyclopropanes Using H2 and Palladium on Charcoal
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The hydrogenolysis of enantioenriched donor–acceptor (D–A) cyclopropanes using H2 (1 atm) and a catalytic amount of palladium on charcoal gave trans-α-alkoxycarbonyl-β-benzyl-γ-lactones or β-substituted γ-aryl-α,α-diesters with high enantiomeric excess. The reaction was also used as a key step in the asymmetric total synthesis of yatein with high ee and excellent dr. This demonstrates the utility of this new protocol for the asymmetric synthesis of trans-α,β-disubstituted γ-butyrolactones. D–A cyclopropanes containing electron-withdrawing groups at the β-position were not susceptible to hydrogenolysis under these conditions. The reductive ring-opening of a D–A cyclopropane using D2 instead of H2 generated the corresponding monodeuterated product.
- Sone, Yoshitomo,Kimura, Yumi,Ota, Ryotaro,Mochizuki, Takehito,Ito, Junki,Nishii, Yoshinori
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supporting information
p. 2842 - 2847
(2017/05/29)
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- Laboratory-Scale Membrane Reactor for the Generation of Anhydrous Diazomethane
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A configurationally simple and robust semibatch apparatus for the in situ on-demand generation of anhydrous solutions of diazomethane (CH2N2) avoiding distillation methods is presented. Diazomethane is produced by base-mediated decomposition of commercially available Diazald within a semipermeable Teflon AF-2400 tubing and subsequently selectively separated from the tubing into a solvent- and substrate-filled flask (tube-in-flask reactor). Reactions with CH2N2 can therefore be performed directly in the flask without dangerous and labor-intensive purification operations or exposure of the operator to CH2N2. The reactor has been employed for the methylation of carboxylic acids, the synthesis of α-chloro ketones and pyrazoles, and palladium-catalyzed cyclopropanation reactions on laboratory scale. The implementation of in-line FTIR technology allowed monitoring of the CH2N2 generation and its consumption. In addition, larger scales (1.8 g diazomethane per hour) could be obtained via parallelization (numbering up) by simply wrapping several membrane tubings into the flask.
- Dallinger, Doris,Pinho, Vagner D.,Gutmann, Bernhard,Kappe, C. Oliver
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p. 5814 - 5823
(2016/07/26)
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- 3,3″-bis(saccharin-6-ylmethyl)-1,1′:3′,1″-terphenyl - Precursor of a new tetradendate bis-bridging ligand
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The title compound (H2tpsac) was synthesized from 6-bromosaccharin and 3,3"-bis(bromomethyl)-m-terphenyl. The ability of tpsac to serve as a tetradentate bis-bridging ligand was demonstrated by the formation of the dinuclear ruthenium(I,I) complexes [Ru2(CO)5(μ,μ- tpsac)]2, [Ru2(CO)4(μ,μ-tpsac)]n, [Ru2(CO)4(PPh3)2(μ,μ-tpsac)], and [Ru2(CO)5(PPh3)(μ,μ-tpsac)]. An X-ray crystal structure analysis of [Ru2(CO)4(PPh 3)2(μ,μ-tpsac)] showed the head-to-tail (or 1,1) arrangement of the two saccharinate coordination sites.
- Buck, Stefan,Maas, Gerhard
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p. 1070 - 1080,11
(2012/12/12)
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- 3,3″-bis(saccharin-6-ylmethyl)-1,1′:3′,1″-terphenyl - Precursor of a new tetradendate bis-bridging ligand
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The title compound (H2tpsac) was synthesized from 6-bromosaccharin and 3,3"-bis(bromomethyl)-m-terphenyl. The ability of tpsac to serve as a tetradentate bis-bridging ligand was demonstrated by the formation of the dinuclear ruthenium(I,I) complexes [Ru2(CO)5(μ,μ- tpsac)]2, [Ru2(CO)4(μ,μ-tpsac)]n, [Ru2(CO)4(PPh3)2(μ,μ-tpsac)], and [Ru2(CO)5(PPh3)(μ,μ-tpsac)]. An X-ray crystal structure analysis of [Ru2(CO)4(PPh 3)2(μ,μ-tpsac)] showed the head-to-tail (or 1,1) arrangement of the two saccharinate coordination sites.
- Buck, Stefan,Maas, Gerhard
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p. 1070 - 1080
(2013/01/15)
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- Synthesis of a novel C2-symmetric bis-oxazoline (=bis[4,5-dihydrooxazole]) and its application as chiral ligand in asymmetric transition metal catalysis
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The new C2-symmetric bis-oxazoline (=bis[4,5-dihydrooxazole]) 2 with a chiral trans-(2R,3R)-2,3-bis(3,5-diphenylphenyl)cyclopropylidene (=trans-(2R,3R)-2,3-bis([1,1′: 3′,1″-terphenyl]-5′-yl) cyclopropylidene) backbone was efficiently synthesized (Scheme). All synthetic steps were easy to perform and led to the desired product in good overall yields. Compound 2 was tested and compared as ligand in several enantioselective catalytic reactions such as palladium(0)-catalyzed enantioselective allylic alkylations and copper(I)-catalyzed enantioselective cyclopropanations and aziridinations. Copyright
- Goek, Yasar,Van Der Eycken, Johan
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experimental part
p. 831 - 838
(2012/06/16)
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- Intermolecular metal-free cyclopropanation of alkenes using tosylhydrazones
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We describe the first general method for the metal-free cyclopropanation of alkenes by using N-tosylhydrazones as an in situ source of diazo compounds. This new method works with a wide variety of alkenes (styrene derivatives, dienes, enynes, and electron-deficient alkenes) by using N-tosylhydrazones derived from various ketones or aldehydes (aromatic, aliphatic, enones). The reaction is performed with the use of K2CO3 as a base to form the diazo species and is compatible with a wide array of functional groups. A new procedure for the synthesis of cyclopropanes by the formal cyclopropanation of carbonyl compounds and alkenes is described. This metal-free reaction proceeds through the base-promoted decomposition of tosylhydrazones. There is significant tolerance of the functional groups, enabling cyclopropanation in the presence of functionalities often not compatible with other methodologies.
- Barluenga, Jose,Quinones, Noelia,Tomas-Gamasa, Maria,Cabal, Maria-Paz
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supporting information; experimental part
p. 2312 - 2317
(2012/06/01)
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- Ruthenium- and rhodium-catalyzed carbenoid reactions of diazoesters in hexaalkylguanidinium-based ionic liquids
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Hexaalkylguanidinium-based room-temperature ionic liquids were investigated as solvents for the cyclopropanation of styrene with diazoacetates catalyzed by Rh2(OAc)4 or [Ru2(μ-OAc) 2(CO)4]n. While the yields of the formed cyclopropanes are much lower compared to the reactions performed in dichloromethane, the diastereomeric ratio is not significantly affected by the change of the reaction medium. Immobilization of the catalysts is only partially successful. In contrast to this intermolecular reaction, the Ru-catalyzed formation of a β-lactam by an intramolecular carbenoid C-H insertion of an α-methoxycarbonyl-α-diazoacetamide occurs in high yield, similar to the Rh2(OAc)4-catalyzed reaction. The cis → trans isomerization of the resulting 1-tert-butyl-3-methoxycarbonyl-4-phenyl-azetidin- 2-one is accelerated in the ionic liquid N,N-dibutyl-N',N'-diethyl-N'',N''- dihexylguanidin-ium triflate.
- Large, Torsten,Mueller, Tobias,Kunkel, Helene,Buck, Stefan,Maas, Gerhard
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experimental part
p. 347 - 353
(2012/07/14)
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- SmI2-mediated reductive cross-coupling reactions of -cyclopropyl nitrones
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Three new α-cyclopropyl nitrones have been synthesized as mechanistic probes for reductive cross-coupling reactions of nitrones. The α-cyclopropylcarbinyl radical intermediate formed by single electron transfer from SmI2 to these nitrones is no
- Burchak, Olga N.,Masson, Geraldine,Py, Sandrine
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scheme or table
p. 1623 - 1626
(2010/09/05)
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- Fragmentation of chloroperoxides: Hypochlorite-mediated dehydration of hydroperoxyacetals to esters
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Hypochlorites efficiently dehydrate hydroperoxyacetals to furnish the corresponding esters. The reaction, which can be accomplished with stoichometric Ca(OCl)2 or with catalytic amounts of t-BuOCl, appears to involve formation and heterolytic fragmentation of secondary chloroperoxides, species not previously described in solution chemistry.
- Fisher, Thomas J.,Dussault, Patrick H.
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experimental part
p. 5615 - 5617
(2010/10/21)
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- Stereo- and regiocontrol in ene-dimerisation and trimerisation of 1-trimethylsilyl-3-phenylcyclopropene
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1-Trimethylsilyl-3-phenylcyclopropene and its 2D-analog undergo a highly stereocontrolled ene-reaction to give a single dimer. Further reaction leads to one or more trimers derived through two ene-reactions. The dimer formed easily undergoes cycloaddition
- Sheshenev, Andrey E.,Baird, Mark S.,Bolesov, Ivan G.,Shashkov, Alexandre S.
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experimental part
p. 10552 - 10564
(2010/03/01)
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- Novel trans-2-aryl-cyclopropylamine analogues as potent and selective dipeptidyl peptidase IV inhibitors
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A series of trans-2-aryl-cyclopropylamine derived compounds were synthesized and evaluated their biological activities against DPP-IV. The structure-activity relationships (SAR) led to the discovery of novel series of DPP-IV inhibitors, having IC50 values of 100 nM with excellent selectivity over the closely related enzymes, DPP8, DPP-II and FAP. The studies identified a potent and selective DPP-IV inhibitor 24b, which exhibited the ability to both significantly inhibit plasma DPP-IV activity in rats and improve glucose tolerance in lean mice and diet induced obese mice.
- Tsai, Ting-Yueh,Hsu, Tsu,Chen, Chiung-Tong,Cheng, Jai-Hong,Yeh, Teng-Kuang,Chen, Xin,Huang, Chung-Yu,Chang, Chung-Nien,Yeh, Kai-Chia,Hsieh, Su-Huei,Chien, Chia-Hui,Chang, Yi-Wei,Huang, Chih-Hsiang,Huang, Yu-Wen,Huang, Chen-Lung,Wu, Ssu-Hui,Wang, Min-Hsien,Lu, Cheng-Tai,Chao, Yu-Sheng,Jiaang, Weir-Torn
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experimental part
p. 2388 - 2399
(2009/09/05)
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- New catalytic system Cu(OAc)2-2,4-lutidine-ZnCl2 for olefin cyclopropanation with methyl diazoacetate
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A new efficient catalytic system consisting of Cu(OAc)2, 2,4-lutidine, and ZnCl2 was found for the cyclopropanation of unsaturated compounds with methyl diazoacetate. In the case of conjugated dienes, the process occurs regioselectively at the most alkylated C=C bond.
- Gareev,Sultanova,Biglova,Dokichev,Tomilov
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experimental part
p. 1784 - 1786
(2011/04/23)
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- One-pot approach for the synthesis of trans-cyclopropyl compounds from aldehydes. Application to the synthesis of GPR40 receptor agonists
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A novel multicatalytic one-pot process providing trans-cyclopropyl compounds from corresponding aldehydes has been developed and applied to the synthesis of GPR40 small molecule agonists. The Royal Society of Chemistry.
- Davi, Micha?l,Lebel, Hélène
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supporting information; experimental part
p. 4974 - 4976
(2009/06/05)
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- Synthesis of polymer bound azabis(oxazoline) ligands and their application in asymmetric cyclopropanations
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Aza(bisoxazoline) ligands were attached to various polymeric supports and the resulting immobilized ligands were evaluated in copper(I)-catalyzed asymmetric cyclopropanations. The efficiency of these transformations depends greatly on the polymeric support, on the protocol being applied for the immobilization of the ligands, and on the preparation of the catalysts.
- Werner, Heiko,Herrerias, Clara I.,Glos, Michael,Gissibl, Anja,Fraile, Jose M.,Perez, Ignacio,Mayoral, Jose A.,Reiser, Oliver
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p. 125 - 132
(2007/10/03)
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- Efficient syntheses of four stable-isotope labeled (1R)-menthyl (1S,2S)-(+)-2-phenylcyclopropanecarboxylates
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Many carbenoid cyclopropanation reactions promoted by chiral catalysts give product mixtures reflecting impressive diastereo- and enantioselectivities. Few provide a single chiral product efficiently. This limitation has been overcome in cyclopropanations of styrene and isotopically labeled styrenes with α-diazoacetates. Convenient syntheses on a 20 g scale of each of four chiral isotopically labeled (1R)-menthyl (1S,2S)-2- phenylcyclopropanecarboxylates (the 1-d-3-13C, 1,(3S)-d2, 1,2,(3S)-d3, and 1,3,3-d3 isotopomers) of better than 99% ee have been realized. The Royal Society of Chemistry 2006.
- Keliher, Edmund J.,Burrell, Richard C.,Chobanian, Harry R.,Conkrite, Karina L.,Shukla, Rajesh,Baldwin, John E.
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p. 2777 - 2784
(2008/09/16)
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- A practical and controllable enantioselective synthesis of 2-phenyl-1-cyclopropanecarboxylates via a camphor-derived sulfonium ylide
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We have developed a practical and controllable enantioselective synthesis of 2-phenyl-1-cyclopropane-carboxylates via camphor-derived sulfonium ylide. The procedure has many advantages such as cheap starting materials, facile synthetic procedures, good yields, excellent diastereoselectivities and high enantioselectivities. Georg Thieme Verlag Stuttgart.
- Huang, Kun,Huang, Zhi-Zhen
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p. 1621 - 1623
(2007/10/03)
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- Dinuclear ruthenium(I) complexes of the type [Ru2(CO) 4L2] with carboxylate or 2-pyridonate ligands: Evaluation as catalysts for olefin cyclopropanation with diazoacetates
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Dinuclear ruthenium(I,I) carboxylate complexes [Ru2(CO) 4(μ-OOCR)2]n (R = CH3 (1a), C3H7 (1b), H (1c), CF3 (1d)) and 2-pyridonate complex [Ru2(CO)4(μ-2-pyridonate)2] n (3) catalyze efficiently the cyclopropanation of alkenes with methyl diazoacetate. High yields are obtained with terminal nucleophilic alkenes (styrene, ethyl vinyl ether, α-methylstyrene), medium yields with 1-hexene, cyclohexene, 4,5-dihydrofuran and 2-methyl-2-butene. The E-selectivity of the cyclopropanes obtained from the monosubstituted alkenes and the cycloalkenes decreases in the order 1b > 1a > 1d > 1c. The cyclopropanation of 2-methyl-2-butene is highly syn-selective. Several complexes of the type [Ru2(CO)4(μ-L1) 2]2 (4) and (5), [Ru2(CO)4(μ- L1)2L2] (L2 = CH3OH, PPh3) (6)-(9) and [Ru2(CO)4(CH 3CN)2(μ-L1)2] (10) and (11), where L1 is a 6-chloro- or 6-bromo-2-pyridonate ligand, are also efficient catalysts. Compared with catalyst 3, a halogen substituent at the pyridonate ligand affects the diastereoselectivity of cyclopropanation only slightly.
- Werle, Thorsten,Sch?ffler, Lutz,Maas, Gerhard
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p. 5562 - 5569
(2007/10/03)
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- Highly diastereoselective hydrostannylation of allyl and homoallyl alcohols with dibutyl(trifluoromethanesulfoxy)stannane
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Dibutyl(trifluoromethanesulfoxy)stannane (Bu2Sn(OTf)H, 1a) was found to be very valuable for highly diastereoselective homolytic hydrostannylation of allyl and homoallyl alcohols. α,β-Disubstituted allyl alcohols and α,γ-disubstituted homoallyl alcohols were converted into γ- and δ-stannylated alcohols with high 1,2-syn and 1,3-syn diastereoselectivity, respectively. The origin of the stereochemical outcomes can be rationalized by conformational fixation of the intermediary β-stannylalkyl radical by coordination of the hydroxy group to the Lewis acidic tin center. Copyright
- Miura, Katsukiyo,Wang, Di,Hosomi, Akira
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p. 9366 - 9367
(2007/10/03)
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- Dinuclear ruthenium(I) triazenide complexes as catalysts for carbenoid cyclopropanation reactions
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The ability of ruthenium(I) triazenide complexes [Ru(CO) 3(ArNNNAr)]2 (Ar = C6H4-4-X, X = CH3, Cl, Br) to catalyze the cyclopropanation of alkenes with methyl diazoacetate is investigated. With terminal alkenes (styrene, ethyl vinyl ether, 1-hexene), the cyclopropanecarboxylic esters are formed in good to high yield and with an E:Z diastereoisomer ratio of about 1.0 in most cases. 2-Methyl-2-butene is cyclopropanated in low yield but with a syn-selectivity up to 90:10.
- Leger, Claus-Dieter,Maas, Gerhard
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p. 573 - 578
(2007/10/03)
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- Bis(oxazoline)·copper(I)-catalyzed enantioselective cyclopropanation of cinnamate esters with diazomethane
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Chiral bis(oxazoline)-copper(I) complexes were found to be effective catalysts for the enantioselective cyclopropanation reaction of trans-cinnamate esters exploiting an argon flow mediated diazomethane addition method. After optimization of the catalyst structure, good yields and enantiomeric excesses were obtained with electron-poor methyl cinnamate derivatives. Sterically demanding esters gave lower yields and enantioselectivities. The correlation between the product enantiopurities and the σ+ values of the aromatic para-substituents was shown to be linear in a Hammet-type plot.
- Charette, Andre B.,Janes, Marc K.,Lebel, Helene
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p. 867 - 872
(2007/10/03)
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- A new chiral ruthenium complex for catalytic asymmetric cyclopropanation
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A new chiral ruthenium complex 6, featured with an N,O-mixed polydentate ligand, was synthesized and characterized. This ruthenium complex showed high efficiency in catalytic cyclopropanations of alkenes with diazoacetates. High trans/cis selectivity and enantioselectivity (up to 96%) were achieved with the readily accessible ethyl diazoacetate as the reagent.
- Tang, Wenjun,Hu, Xinquan,Zhang, Xumu
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p. 3075 - 3078
(2007/10/03)
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- Cyclopropane formation by copper-catalysed indirect electroreductive coupling of activated olefins and activated α,α,α-trichloro or gem-dichloro compounds
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Cyclopropanes have been prepared in good yields by indirect electroreductive coupling of activated olefins and activated α,α,α-trichloro or gem-dichloro compounds (Cl3CCO2Me, PhCCl3, Ph2CCl2, PhCHCl2). This process, using a copper complex in catalytic amountss is convenient for the reagent couple activated olefin/activated polyhalide, whatever the reduction potential of each reagent relative to each other. The main advantage of our electrochemical process is that it does not require the use of hazardous, toxic, or not easily prepared reagents like diazocompounds or diazirines.
- Sengmany,Leonel,Paugam,Nedelec
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p. 533 - 537
(2007/10/03)
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- Highly enantioselective cyclopropanation of styrenes and diazoacetates catalyzed by 3-oxobutylideneaminatocobalt(II) complexes, part 1. Designs of cobalt complex catalysts and the effects of donating ligands
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Highly enantioselective cyclopropanation of styrene derivatives and diazoacetates was effectively catalyzed by reasonably designed 3-oxobutylideneaminatocobalt(II) complexes, whose ligands were prepared from 1,2-dimesitylethyl-enediamine and alkyl 3-oxobutanoates. The steric demand of the diamine unit of the complexes seriously influenced the enantioselectivity, and the ester groups on their side chains somewhat improved the trans-selectivity. Addition of a catalytic amount of N-methylimidazole significantly accelerated the reaction and enhanced the enantioselectivity due to its coordination to the center cobalt atom of the complex as an axial ligand. Alcoholic or aqueous alcoholic solvents were also effective particularly for the cyclopropanation of 1-substituted 1-phenylethylenes to achieve high enantioselectivity in aqueous methanol.
- Ikeno, Taketo,Sato, Mitsuo,Sekino, Hiroyuki,Nishizuka, Asae,Yamada, Tohru
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p. 2139 - 2150
(2007/10/03)
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- Asymmetric inter- and intramolecular cyclopropanation of alkenes catalyzed by chiral ruthenium porphyrins. Synthesis and crystal structure of a chiral metalloporphyrin carbene complex
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Extensive investigations of asymmetric intermolecular cyclopropanation of terminal alkenes with diazoacetates catalyzed by ruthenium porphyrin [Ru(P*)(CO)(EtOH)] (1, H2P* = 5,10,15,20-tetrakis-{(1S,4R,5R,8S)-1,2,3,4,5,6,7,8-octahydro-1,4:5,8- dimethanoanthracene-9-yl}porphyrin) and the application of catalyst 1 to asymmetric intramolecular cyclopropanation of allylic or homoallylic diazoacetates are described. The intermolecular cyclopropanation of styrene and its derivatives with ethyl diazoacetate afforded the corresponding cyclopropyl esters in up to 98% ee with high trans/cis ratios of up to 36 and extremely high catalyst turnovers of up to 1.1 × 104. Examination of the effects of temperature, diazoacetate, solvent, and substituent in the intermolecular cyclopropanation reveals that (i) both enantioselectivity and trans selectivity increase with decreasing temperature, (ii) sterically encumbered diazoacetates N2CHCO2R such as R = But, and donor solvents, such as diethyl ether and tetrahydrofuran, are beneficial to the trans selectivity, and (iii) electron-donating para substituents on styrene accelerate the cyclopropanations, with the log(kx/kH) vs σ+ plot for para-substituted styrenes p-X-C6H4CH=CH2 (X = MeO, Me, Cl, CF3) exhibiting good linearity with a small negative ρ+ value of -0.44 ± 0.09. In the case of intramolecular cyclopropanation, complex 1 promoted the decomposition of a series of allylic diazoacetates to form the cyclopropyl lactones in up to 85% ee, contributing the first efficient metalloporphyrin catalyst for an asymmetric intramolecular cyclopropanation. Both the inter- and intramolecular cyclopropanations were proposed to proceed via a reactive chiral ruthenium carbene intermediate. The enantioselectivities in these processes were rationalized on the basis of the X-ray crystal structures of closely related stable chiral carbene complexes [Ru(P*)(CPh2)] (2) and [Ru(P*)(C(Ph)-CO2CH2CH=CH2)] (3) obtained from reactions of complex 1 with N2CPh2 and N2C(Ph)CO2CH2CH=CH2, respectively.
- Che,Huang,Lee,Li,Lai,Kwong,Teng,Lee,Lo,Peng,Zhou
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p. 4119 - 4129
(2007/10/03)
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- Arylcyclopropanecarboxyl guanidines as novel, potent, and selective inhibitors of the sodium hydrogen exchanger isoform-1
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A novel series of arylcyclopropanecarboxyl guanidines was synthesized and evaluated for activity against the sodium hydrogen exchanger isoform-1 (NHE-1). In biological assays conducted in an AP1 cell line expressing the human NHE-1 isoform, the starting cyclopropane 3a (IC50 = 3.5 μM) shows inhibitory activity comparable to cariporide (IC50 = 3.4 μM). Structure-activity relationships are used to optimize the affinity of various acyl guanidines for NHE-1 by screening the effect of substituents at both aryl and cyclopropyl rings. It is demonstrated that introduction of appropriate hydrophobic groups at the phenyl ring and a gem-dimethyl group at the cyclopropane ring enhances the NHE-1 inhibitory activity by up to 3 orders of magnitude (compound 7f, IC50 = 0.003 μM). In addition, the gem-dimethyl series of analogues seem to display improved oral bioavailability and longer plasma half-life in rats. Furthermore, the lead benzodihydrofuranyl analogue 1 (BMS-284640) shows over 380-fold increased NHE-1 inhibitory activity as well as improved selectivity for NHE-1 over NHE-2 compared to cariporide.
- Ahmad,Doweyko,Dugar,Grazier,Ngu,Wu,Yost,Chen,Gougoutas,DiMarco,Lan,Gavin,Chen,Dorso,Serafino,Kirby,Atwal
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p. 3302 - 3310
(2007/10/03)
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- Aza-bis(oxazolines): New chiral ligands for asymmetric catalysis
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diagram presented Aza-bis(oxazolines) are introduced as chiral ligands for asymmetric catalysis combining the advantages of easy availability of bis(oxazolines) and backbone variability of aza-semicorrins. Especially, the title ligands could be attached t
- Glos, Martin,Reiser, Oliver
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p. 2045 - 2048
(2007/10/03)
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- Concave reagents 32: Syn- and anti-selective cyclopropanation of alkenes with diazoacetates catalyzed by copper(I) complexes of concave 1,10- phenanthrolines
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Two classes of concave 1,10-phenanthroline ligands 1 and 2 have been used in the copper(I) catalyzed cyclopropanation of several acyclic and cyclic alkenes 3 with three diazoacetates 4-6. The bimacrocyclic 2,9-diaryl- 1,10-phenanthrolines 1 favor the anti(trans- or exo-) cyclopropanation with anti/syn-selectivities of up to > 99:1 (8g). In contrast, with the 1,10- phenanthroline bridged calix[6]arenes 2 as ligands a rarely observed syn- selective cyclopropanation was achieved. Methyl diazoacetate (6) showed the best syn-selectivities with anti/syn-ratios of up to 14:86 (9g).
- L?ffler, Frank,Hagen, Martin,Lüning, Ulrich
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p. 1826 - 1828
(2007/10/03)
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- The effect of electrochemically formed aluminum salts on the electrochemical cyclisation of methyl cinnamate
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Electrochemical cyclisation of methyl cinnamate with dielectrophiles has been improved by the presence of an aluminum salt which was pre-formed in situ by the electrolysis of a carboxylic acid with a sacrificial aluminum anode. High yields of three, five and six-membered cyclic products have been obtained in the reactions of methyl cinnamate with dichloromethane, 1,3- dibromopropane, and 1,4-dibromobutane.
- Guellue, Mustafa
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p. 3225 - 3228
(2007/10/03)
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- Highly enantioselective cyclopropanation of styrenes with diazoacetates catalyzed by optically active β-ketoiminato cobalt(II) complexes
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The highly enantioselective cyclopropanation of styrenes with diazoacetates was achieved using reasonably designed β-ketoiminato cobalt(II) complex catalysts. In the presence of optically active cobalt(II) complexes derived from optically active 1,2-(2,4,
- Ikeno, Taketo,Sato, Mitsuo,Yamada, Tohru
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p. 1345 - 1346
(2007/10/03)
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- Single-chiral bis(oxazolinyl)pyridine (pybox). Efficiency in asymmetric catalytic cyclopropanation
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Single-chiral bis(oxazolinyl)pyridine ligands were examined as ligands for ruthenium-catalyzed asymmetric catalytic cyclopropanation of olefins: enantioselectivities up to 94% for the trans-cyclopropane were observed.
- Nishiyama, Hisao,Soeda, Norikazu,Naito, Tomonari,Motoyama, Yukihiro
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p. 2865 - 2869
(2007/10/03)
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- Cyclopropanation reactions catalysed by ruthenium complexes with new anionic phosphine ligands
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Novel ruthenium complexes with anionic phosphine ligands were found to be efficient In the catalytic cyclopropanation reaction of olefins with ethyl diazoacetate.
- Demonceau,Simal,Noels,Vinas,Nunez,Teixidor
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p. 4079 - 4082
(2007/10/03)
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- Catalytic Asymmetric Synthesis of Cyclopropane Derivatives with Chiral Ruthenium Complexes: Isolation of Intermediate Carbene Complex
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A chiral ruthenium(II)-bis(2-oxazolin-2-yl)pyridine catalyst prepared in situ from optically active bis(2-oxazolin-2-yl)pyridine (Pybox-ip) (2) and [RuCl2(p-cymene)]2 (1) exhibited efficient activity for the asymmetric cyclopropanation (ACP) of styrene and several diazoacetates to give the corresponding trans- and cis-2-phenylcyclopropane-1-carboxylates (3 and 4) in good yields (66-87%). A mixture of 1 and 2 in an atmosphere of ethylene produced the trans-RuCl2(Pybox-ip)(ethylene) complex (5), which also proved to be a powerful catalyst for ACP. The stereoselectivity of the trans- and cis-cyclopropanes were from 90:10 up to 98:2, and their enantioselectivities reached 97%. A catalytic system with 5 could be used for several olefins (6-8) and internal olefins (12 and 13). The non-chiral Ru-Pybox-dihydro catalyst 16 exhibited asymmetric induction with 39% ees of 3 with d- and l-menthyl diazoacetates, and kept a high trans- and cis-stereoselection of 97:3. 2,6-Di-tert-butyl-methylphenyl diazoacetate 17 reacted with the complex 5 to give a stable carbene complex 18, which was characherized by NMR study. The complex 18 exhibited a carbene transfer reaction with styrene at 80°C to give only trans-cyclopropane 3 in 55 %ee.
- Nishiyama
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p. 158 - 164
(2007/10/03)
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- Aryloxycarbonylcarbene Complexes of Bis(oxazolinyl)pyridineruthenium as Active Intermediates in Asymmetric Catalytic Cyclopropanations
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The reaction of (1) (pybox = 2,6-bispyridine) and 2,6-di-tert-butyltolyl diazoacetate (4) (DBTDA) in benzene at 50 deg C gave a stable 2,6-di-butyltolylcarbonylcarbene - ruthenium complex 5 in 94percent y
- Park, Soon-Bong,Sakata, Naoya,Nishiyama, Hisao
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p. 303 - 306
(2007/10/03)
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- trans-2-Aryl-N,N-dipropylcyclopropylamines: Synthesis and interactions with 5-HT(1A) receptors
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Twelve N,N-dipropyl-substituted derivatives of trans-2- arylcyclopropylamine have been prepared and assayed for their ability to displace [3H]-8-OH-DPAT from rat brain 5-HT(1A) receptors. The new derivatives include phenyl (7a), bromo- (7b) and fluorophenyl (7c-e), 2- methoxy-5-fluorophenyl (7h), and 2-hydroxy-5-fluorophenyl (71) as well as trifluoromethylphenyl (7f) and 2,3-dichlorophenyl (7g) analogues. In the present series of compounds, electron-withdrawing substituents in the phenyl ring appear to decrease the affinity for 5-HT(1A) receptors. In contrast, electron-rich aryl groups, such as 2- or 3-thienyl (7j and 7k, respectively), provide compounds with high affinity. The additional bulk produced by the aromatic moiety in the 2-benzothienyl derivative 7i appears to be detrimental to 5-HT(1A) receptor affinity. The racemic mixtures of the interesting 7j and 7l were resolved into the enantiomers; 7j and 7l exhibited a high enantiomeric 5-HT(1A) receptor affinity ratio (75-fold and 100-fold, respectively). The enantiomers of 7j and 7l were evaluated in vivo by use of biochemical and behavioral tests in rats. Compound (1R,2R)-7j behaved as a partial agonist whereas (1R,2S)-7l appeared as an efficacious 5-HT(1A) receptor agonist, stimulating both autoreceptors and postsynaptic receptors.
- Vallgarda,Appelberg,Arvidsson,Hjorth,Svensson,Hacksell
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p. 1485 - 1493
(2007/10/03)
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- Chiral Ruthenium(II)-Bis(2-oxazolin-2-yl)pyridine Complexes. Asymmetric Catalytic Cyclopropanation of Olefins and Diazoacetates
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A chiral ruthenium(II)-bis(2-oxazolin-2-yl)pyridine catalyst prepared in situ from optically active bis(2-oxazolin-2-yl)pyridine (Pybox-ip) (2) and 2 (1) exhibited efficient activity for the asymmetric cyclopropanation (ACP) of styrene and several diazoacetates to give the corresponding trans- and cis-2-phenylcyclopropane-1-carboxylates (3 and 4) in good yields (66-87percent).A mixture of 1 and 2 in an atmosphere of ethylene produced the trans-RuCl2 (Pybox-ip)(ethylene) complex (5), which also proved to be a poweful catalyst for ACP.The stereoselectivity of the trans- and cis-cyclopropanes were from 90:10 up to 98:2, and their enantioselectivities reached 97percent.A catalytic system with 5 could be used for several olefins and internal olefins.A concerted mechanism of ACP with the Ru-Pybox catalyst was postulated on the basis of the stereospecificity with deuterated styrene.Other substituents, such as ethyl, s-butyl, benzyl, and phenyl on the oxazoline rings of Pybox in place of the isopropyl group were also examined, and were found to exhibit a similar high trans-stereoselection and a high enantioselectivity of the cyclopropane products; ex . with Ru-Pybox-ethyl 91:9 of 3:4 and 82percent ee for 3.The non-chiral Ru-Pybox-dihydro catalyst exhibited asymmetric induction with 39percent ees of 3 with d- and l-menthyl diazoacetates, and kept a high trans- and cis-stereoselection of 97-3.
- Nishiyama, Hisao,Itoh, Yoshiki,Sugawara, Yuji,Matsumoto, Hideki,Aoki, Katsuyuki,Itoh, Kenji
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p. 1247 - 1262
(2007/10/03)
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- Reductive Carbonylation of gem-Dihalogenocyclopropanes by Pentacarbonyliron(0) in the Presence of Sodium Methoxide
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The reaction of gem-dihalogenocyclopropanes derivatives with (tetracarbonyl)(methoxycarbonylato)ferrate(I-) has been investigated; gem-dibromocyclopropanes and gem-chlorobromocyclopropane derivatives are reduced and carbonylated.It could be shown that a bromo ester such as methyl 1-bromo-2-phenylcyclopropanecarboxylate is an intermediate in the transformation of 1,1-dibromo-2-phenylcyclopropane into methyl cis- and trans-2-phenylcyclopropanecarboxylates and dimethyl 2-phenyl-1,1-cyclopropanedicarboxylate.
- Reyne, Francoise,Waegell, Bernard,Brun, Pierre
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p. 1162 - 1167
(2007/10/02)
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- Asymmetric Cyclopropanation Using New Chiral Auxiliaries Derived from D-Fructose
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Acetals of α,β-unsaturated aldehydes with 3-O-alkylated derivatives of 1,2-O-isopropylidene-β-D-fructopyranose and 1,2-O-isopropylidene-β-D-psicopyranose, which are readily available from D-fructose, were cyclopropanated with Et2Zn and CH2I2 with good diastereoselectivity.The effects of structure of the acetals on enantioselectivity were examined.
- Kang, Jahyo,Lim, Geun Jho,Yoon, Suk Kyoon,Kim, Moohi Yoo
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p. 564 - 577
(2007/10/02)
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- Total Diastereoselective Synthesis of Chromium Cyclopropylcarbene Complexes
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Trans-substituted chromium cyclopropylmethoxycarbene complexes 4 have been obtained with total diastereoselectivity through a conjugated addition of in situ generated chloromethyllithium to vinylmethoxycarbene chromium complexes.
- Barluenga, Jose,Bernad, Pablo L.,Concellon, Jose M.
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p. 3937 - 3940
(2007/10/02)
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- Polymeric dicarbonyl ruthenium(I) acetate - An efficient catalyst for alkene cyclopropanation with diazoacetates
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The polymeric complex [Ru2(CO)4(μ-OAc)2](n) is the first Ru(I) catalyst that efficiently catalyzes cyclopropanation of alkenes with diazoacetic esters. The related dinuclear catalyst Ru2(CO)4(μ-OAc)2(MeCN)2 shows a similar performance only for cyclopropanation of monosubstituted alkenes.
- Maas,Werle,Alt,Mayer
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p. 881 - 888
(2007/10/02)
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- 184. Stereoselective Hydrolysis of Substituted Cyclopropanedicarboxylates with Pig Liver Esterase
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The hydrolysis of the meso-cyclopropane-1,2-dicarboxylates 1a-3a, 4, 5a, 6a, and 9, containing various substituents at C(3), and of the rac-3-phenylcyclopropane-1,2-dicarboxylates 7a, 8a, and 10 with pig liver esterase (PLE) is described.The stereoselectivity and absolute configurations of the products were determined.An interpretation of results was attempted on the basis of a recent active-site model for PLE.
- Walser, Paula,Renold, Peter,N'Goka, Victor,Hosseinzadeh, Fatemeh,Tamm, Christoph
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p. 1941 - 1952
(2007/10/02)
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- Mechanistic Study of a Synthetically Useful Monooxygenase Model Using the Hypersensitive Probe trans-2-Phenyl-1-vinylcyclopropane
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The use of trans-2-phenyl-1-vinylcyclopropane as a hypersensitive probe to study the epoxidation mechanisms of monooxygenases and their models is described; the high yield epoxide formation indicates that the Mn(III) salen mediated epoxidation of unfuncti
- Fu, Hong,Look, Gary C.,Zhang, Wei,Jacobsen, Eric N.,Wong, Chi-Huey
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p. 6497 - 6500
(2007/10/02)
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