- Ring closing alkyne metathesis: Stereoselective synthesis of civetone
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A concise and stereoselective synthesis of the macrocyclic musk civetone 6 is reported starting from readily available 9-undecynol. The key steps comprise a ring closing metathesis of diyne 4 followed by Lindlar reduction of the resulting cycloalkyne 5. The cyclization can be effected either by using catalytic amounts of the Schrock alkylidyne complex (t-BuO)3W=CCMe3 or by means of an in situ catalyst mixture generated from Mo(CO)6 and p-trifluoromethylphenol. Both catalyst systems turned out to be compatible with the unprotected ketone function of the substrate.
- Fürstner, Alois,Seidel, Günter
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- Continuous Flow Z-Stereoselective Olefin Metathesis: Development and Applications in the Synthesis of Pheromones and Macrocyclic Odorant Molecules**
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The first continuous flow Z-selective olefin metathesis process is reported. Key to realizing this process was the adequate choice of stereoselective catalysts combined with the design of an appropriate continuous reactor setup. The designed continuous process permits various self-, cross- and macro-ring-closing-metathesis reactions, delivering products in high selectivity and short residence times. This technique is exemplified by direct application to the preparation of a range of pheromones and macrocyclic odorant molecules and culminates in a telescoped Z-selective cross-metathesis/ Dieckmann cyclisation sequence to access (Z)-Civetone, incorporating a serial array of continually stirred tank reactors.
- Browne, Duncan L.,Colombel-Rouen, Sophie,Crévisy, Christophe,Curbet, Idriss,Mauduit, Marc,McBride, Tom,Morvan, Jennifer,Roisnel, Thierry
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supporting information
p. 19685 - 19690
(2021/08/06)
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- Highly selective macrocyclic ring-closing metathesis of terminal olefins in non-chlorinated solvents at low dilution
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A set of new ruthenium-indenylidene complexes bearing two unsymmetrical unsaturated N-cycloalkyl-NHC ligands were synthesized. These catalysts proved to be highly selective in the macrocyclic ring-closing metathesis performed in non-chlorinated solvents at low dilution (0.01 M). Without the requirement of benzoquinone derivatives to prevent the isomerisation side reactions, this environmentally friendly catalytic process promoted the synthesis of macrocyclic odorant molecules with remarkable >99% purity.
- Dumas, Adrien,Colombel-Rouen, Sophie,Curbet, Idriss,Forcher, Gwénael,Tripoteau, Fabien,Caijo, Frédéric,Queval, Pierre,Rouen, Mathieu,Baslé, Olivier,Mauduit, Marc
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p. 436 - 443
(2019/01/28)
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- Olefin Metathesis in Confined Geometries: A Biomimetic Approach toward Selective Macrocyclization
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The synthesis of macrocycles is severely impeded by concomitant oligomer formation. Here, we present a biomimetic approach that utilizes spatial confinement to increase macrocyclization selectivity in the ring-closing metathesis of various dienes at elevated substrate concentration up to 25 mM using an olefin metathesis catalyst selectively immobilized inside ordered mesoporous silicas with defined pore diameters. By this approach, the ratio between macro(mono)cyclization (MMC) product and all undesired oligomerization products (O) resulting from acyclic diene metathesis polymerization was increased from 0.55, corresponding to 35% MMC product obtained with the homogeneous catalyst, up to 1.49, corresponding to 60% MMC product. A correlation between the MMC/O ratio and the substrate-to-pore-size ratio was successfully established. Modification of the inner pore surface with dimethoxydimethylsilane allowed fine-tuning the effective pore size and reversing surface polarity, which resulted in a further increase of the MMC/O ratio up to 2.2, corresponding to >68% MMC product. Molecular-level simulations in model pore geometries help to rationalize the complex interplay between spatial confinement, specific (substrate and product) interaction with the pore surface, and diffusive transport. These effects can be synergistically adjusted for optimum selectivity by suitable surface modification.
- Ziegler, Felix,Teske, Johannes,Elser, Iris,Dyballa, Michael,Frey, Wolfgang,Kraus, Hamzeh,Hansen, Niels,Rybka, Julia,Tallarek, Ulrich,Buchmeiser, Michael R.
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supporting information
p. 19014 - 19022
(2019/11/28)
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- METHOD OF CYCLIC COMPOUNDS PRODUCTION IN OLEFINE METATHESIS REACTION AND USE OF RUTHENIUM CATALYSTS IN PRODUCTION OF CYCLIC OLEFINS IN OLEFINE METATHESIS REACTION
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The invention relates to a method for the preparation of cyclic compounds in the metathesis of olefins from acyclic dienes comprising terminal and/or non-terminal C=C double bonds; the invention also relates to the use of homogeneous ruthenium complexes and homogeneous ruthenium complexes deposited on a solid support as catalysts and/or pre-catalysts for the preparation of cyclic olefins in olefin metathesis reactions. Formula (I)
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Page/Page column 61
(2018/11/22)
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- Fluorinated Musk Fragrances: The CF2Group as a Conformational Bias Influencing the Odour of Civetone and (R)-Muscone
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The difluoromethylene (CF2) group has a strong tendency to adopt corner over edge locations in aliphatic macrocycles. In this study, the CF2group has been introduced into musk relevant macrocyclic ketones. Nine civetone and five muscone analogues have been prepared by synthesis for structure and odour comparisons. X-ray studies indeed show that the CF2groups influence ring structure and they give some insight into the preferred ring conformations, triggering a musk odour as determined in a professional perfumery environment. The historical conformational model of Bersuker and co-workers for musk fragrance generally holds, and structures that become distorted from this consensus, by the particular placement of the CF2groups, lose their musk fragrance and become less pleasant.
- Callejo, Ricardo,Corr, Michael J.,Yang, Mingyan,Wang, Mingan,Cordes, David B.,Slawin, Alexandra M. Z.,O'Hagan, David
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supporting information
p. 8137 - 8151
(2016/06/13)
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- Z-SELECTIVE METATHESIS CATALYSTS
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A novel chelated ruthenium-based metathesis catalyst bearing an N-2,6- diisopropylphenyl group is reported and displays near-perfect selectivity for the Z-olefin (>95%), as well as unparalleled TONs of up to 7,400, in a variety of homodimerization and industrially relevant metathesis reactions. This derivative and other new catalytically-active species were synthesized using an improved method employing sodium carboxylates to induce the salt metathesis and C-H activation of these chelated complexes. All of these new ruthenium-based catalysts are highly Z-selective in the homodimerization of terminal olefins.
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Paragraph 00076; 00079
(2014/07/07)
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- Stereoselective access to Z and e macrocycles by ruthenium-catalyzed Z-selective ring-closing metathesis and ethenolysis
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The first report of Z-selective macrocyclizations using a ruthenium-based metathesis catalyst is described. The selectivity for Z macrocycles is consistently high for a diverse set of substrates with a variety of functional groups and ring sizes. The same catalyst was also employed for the Z-selective ethenolysis of a mixture of E and Z macrocycles, providing the pure E isomer. Notably, an ethylene pressure of only 1 atm was required. These methodologies were successfully applied to the construction of several olfactory macrocycles as well as the formal total synthesis of the cytotoxic alkaloid motuporamine C.
- Marx, Vanessa M.,Herbert, Myles B.,Keitz, Benjamin K.,Grubbs, Robert H.
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- Highly active ruthenium metathesis catalysts exhibiting unprecedented activity and Z-selectivity
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A novel chelated ruthenium-based metathesis catalyst bearing an N-2,6-diisopropylphenyl group is reported and displays near-perfect selectivity for the Z-olefin (>95%), as well as unparalleled TONs of up to 7400, in a variety of homodimerization and industrially relevant metathesis reactions. This derivative and other new catalytically active species were synthesized using an improved method employing sodium carboxylates to induce the salt metathesis and C-H activation of these chelated complexes. All of these new ruthenium-based catalysts are highly Z-selective in the homodimerization of terminal olefins.
- Rosebrugh, Lauren E.,Herbert, Myles B.,Marx, Vanessa M.,Keitz, Benjamin K.,Grubbs, Robert H.
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supporting information
p. 1276 - 1279
(2013/03/14)
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- (Z)-8-CYCLOHEPTADECENE-1-ONE USED AS A PERFUME
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The invention relates to (Z)-8-cycloheptadecene-1-one which is used as a perfume, in addition to mixture of perfume or aroma substances comprising (Z)-8-cycloheptadecene-1-one and one or more additional perfume or aroma substances.
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Page/Page column 35-36
(2010/10/20)
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- Processes for the preparation of macrocyclic ketones
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Disclosed are a process of subjecting a diester of a long-chain dicarboxylic acid having 18 to 21 carbon atoms to intramolecular condensation in the presence of titanium tetrachloride or zirconium tetrachloride and a trialkylamine to form an alpha-alkoxycarbonylated macrocyclic ketone, and a process for producing a macrocyclic ketone by hydrolyzing an alpha-alkoxycarbonylated macrocyclic ketone obtained by the process and then subjecting the hydrolyzate to decarboxylation. The invention provides a process for producing a macrocyclic ketone efficiently, which permits high concentration synthesis.
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- Practical Synthesis of (Z)-Civetone Utilizing Ti-Dieckmann Condensation
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An efficient, practical, and stereocontrolled synthesis of (Z)-civetone (1), a representative musk perfume, has been performed utilizing a Ti-Dieckmann (intramolecular Ti-Claisen) condensation of dimethyl (Z)-9-octadecenedioate (3) as the key step. This cyclization reaction has some advantages compared with the traditional basic Dieckmann condensation such as higher concentration (100-300 mM), lower reaction temperature (0-5°C), shorter reaction time (1-3 h), use of environmentally benign (low toxicity and safe) reagents (TiCl4 and Et3N or Bu3N), and economical reagents and solvents. 15-, 17-, and 19-membered saturated β-ketoesters (6-8) were also prepared by the present method.
- Tanabe, Yoo,Makita, Atsushi,Funakoshi, Syunsuke,Hamasaki, Ryota,Kawakusu, Tetsuo
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p. 507 - 510
(2007/10/03)
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- Novel ruthenium(II)2 carboxylates as catalysts for alkene metathesis
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The reactions of [Ru(=CHR)Cl2(PCy3)2] (1: R = Ph; 1a: R = -CH=CPh2) with silver salts of carboxylic acids afforded new dimeric complexes of the general formula [Ru2(=CHR)2(R′CO2)2 (μ-R′CO2)2(PCy3)2 (-H2O)] (2: R = Ph, R′ = CF3; 3: R = Ph, R′ = C2F5; 4: R = -CH=CPh2, R′ = CF3; 5: R = Ph, R′ = C6F5; 6: R = -CH=CPh2, R′ = C6F5; 7: R = -CH=CPh2, R′ = CCl3) in good yields. With R′ = CF3, C2F5 or CCl3 these complexes are active catalysts for metathesis of acyclic alkenes, including unsaturated fatty acid esters, as well as for ring closing metathesis. The reactivity of these complexes with bases and weak donor solvents has been studied and their half-life times in several media were determined.
- Buchowicz, Wlodzimierz,Ingold, Florent,Mol, Johannes C.,Lutz, Martin,Spek, Anthony L.
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p. 2842 - 2847
(2007/10/03)
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- A highly efficient synthesis of civetone
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A highly efficient synthesis of civetone has been performed by joining two crucial reactions; (a) Ti-Claisen condensation and (b) intramolecular olefin metathesis using Grubbs' reagent. This synthesis includes not only a stepwise method (A) but also a one-pot method (B). (C) 2000 Elsevier Science Ltd.
- Hamasaki, Ryota,Funakoshi, Syunsuke,Misaki, Tomonori,Tanabe, Yoo
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p. 7423 - 7425
(2007/10/03)
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- Synthesis of Civetone from Palm Oil Products
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Methathesis of ethyl oleate, catalyzed by WCl6 and SnMe4, provided diethyl 9-octadecenedioate (the desired starting material for the synthesis of civetone) in 99percent yield.Dieckmann condensation of diethyl 9-octadecenedioate gave 2-ethoxycarbonyl-9-cycloheptadecenone (63percent yield), the hydrolysis-decarboxylation reaction of which yielded civetone (93percent).Identiffication of all products was by 1H nuclear magnetic resonance, infrared and mass spectroscopic data.This is the first report of the synthesis of civetone from palm oil-derived products.KEY WORDS: Civet, civetone, diethyl 9-octadecenedioate, 2-ethoxycarbonyl-9-cycloheptadecenone, ethyl oleate, metathesis, palm oil.
- Choo, Yuen-May,Ooi, Kay-Eng,Ooi, Ing-Hong
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p. 911 - 913
(2007/10/02)
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- STEREOSPEZIFISCHER AUFBAU UNGESTAETTIGTER MACROCYCLISCHER KETONE
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Monoacetals of ο,ο'-dialdehydes 3 are converted (Z)-stereospecifically into (Z)-unsaturated ο-acetal-carboxylic-acids 5 and 12, respectively.Replacement of the hydroxylic group by the ylid function, followed by acetal cleavage and an intramolecular (E)-stereospecific Wittig reaction yields (E,Z)-cyclodienones 10 and 14, respectively.Subsequent reduction of 14 affords civetone 15.
- Bestmann, Hans Juergen,Luetke, Harry
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p. 1707 - 1710
(2007/10/02)
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- Process for purifying macrocyclic ketones
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A macrocyclic ketone having a 15- to 17-membered ring is produced from an α,ω-long chain dicarboxylic acid ester by the Dieckmann condensation reaction, followed by hydrolysis/decarboxylation reaction and then purification. The macrocyclic ketone is purified by subjecting the ketone to steam distillation in the presence of a non-volatile base.
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