- General, Divergent Platform for Diastereoselective Synthesis of trans-Cyclooctenes with High Reactivity and Favorable Physiochemical Properties**
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trans-Cyclooctenes (TCOs) are essential partners in the fastest known bioorthogonal reactions, but current synthetic methods are limited by poor diastereoselectivity. Especially hard to access are hydrophilic TCOs with favorable physicochemical properties for live cell or in vivo experiments. Described is a new class of TCOs, “a-TCOs”, prepared in high yield by stereocontrolled 1,2-additions of nucleophiles to trans-cyclooct-4-enone, which itself was prepared on a large scale in two steps from 1,5-cyclooctadiene. Computational transition-state models rationalize the diastereoselectivity of 1,2-additions to deliver a-TCO products, which were also shown to be more reactive than standard TCOs and less hydrophobic than even a trans-oxocene analogue. Illustrating the favorable physicochemical properties of a-TCOs, a fluorescent TAMRA derivative in live HeLa cells was shown to be cell-permeable through intracellular Diels–Alder chemistry and to wash out more rapidly than other TCOs.
- Pigga, Jessica E.,Rosenberger, Julia E.,Jemas, Andrew,Boyd, Samantha J.,Dmitrenko, Olga,Xie, Yixin,Fox, Joseph M.
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supporting information
p. 14975 - 14980
(2021/05/31)
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- A Simple, Readily Accessible, and Effective Apparatus for the Photoisomerization of cis -Cyclooctenes to trans -Cyclooctenes
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A simple, cost effective, and readily accessible apparatus for the photoisomerization of cis -cyclooctenes to trans -cyclooctenes is described. Utilizing only FEP tubing, aluminum vent pipe, a household germicidal lamp, and a flash chromatography system, trans -cyclooctenes can be prepared in good yield.
- Pickel, Thomas C.,Genung, Nathan E.,Guckian, Kevin M.,Shi, Xianglin
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supporting information
p. 1711 - 1713
(2021/08/10)
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- A Bioorthogonal Click Chemistry Toolbox for Targeted Synthesis of Branched and Well-Defined Protein–Protein Conjugates
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Bioorthogonal chemistry holds great potential to generate difficult-to-access protein–protein conjugate architectures. Current applications are hampered by challenging protein expression systems, slow conjugation chemistry, use of undesirable catalysts, or often do not result in quantitative product formation. Here we present a highly efficient technology for protein functionalization with commonly used bioorthogonal motifs for Diels–Alder cycloaddition with inverse electron demand (DAinv). With the aim of precisely generating branched protein chimeras, we systematically assessed the reactivity, stability and side product formation of various bioorthogonal chemistries directly at the protein level. We demonstrate the efficiency and versatility of our conjugation platform using different functional proteins and the therapeutic antibody trastuzumab. This technology enables fast and routine access to tailored and hitherto inaccessible protein chimeras useful for a variety of scientific disciplines. We expect our work to substantially enhance antibody applications such as immunodetection and protein toxin-based targeted cancer therapies.
- Baalmann, Mathis,Bitsch, Sebastian,Deweid, Lukas,Ilkenhans, Nadja,Kolmar, Harald,Neises, Laura,Schneider, Hendrik,Werther, Philipp,Wilhelm, Jonas,Wolfring, Martin,Wombacher, Richard,Ziegler, Michael J.
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supporting information
p. 12885 - 12893
(2020/06/02)
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- Optimization of IEDDA bioorthogonal system: Efficient process to improve trans-cyclooctene/tetrazine interaction
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The antibody pretargeting approach for radioimmunotherapy (RIT) using inverse electron demand Diels-Alder cycloaddition (IEDDA) constitutes an emerging theranostic approach for solid cancers. However, IEDDA pretargeting has not reached clinical trial. The major limitation of the IEDDA strategy depends largely on trans-cyclooctene (TCO) stability. Indeed, TCO may isomerize into the more stable but unreactive cis-cyclooctene (CCO), leading to a drastic decrease of IEDDA efficiency. We have thus developed both efficient and reproducible synthetic pathways and analytical follow up for (PEGylated) TCO derivatives, providing high TCO isomeric purity for antibody modification. We have set up an original process to limit the isomerization of TCO to CCO before the mAbs’ functionalization to allow high TCO/tetrazine cycloaddition.
- Béquignat, Jean-Baptiste,Boucheix, Claude,Canitrot, Damien,Chezal, Jean-Michel,Degoul, Fran?oise,Miot-Noirault, Elisabeth,Moreau, Emmanuel,Navarro-Teulon, Isabelle,Quintana, Mercedes,Rondon, Aurélie,Taiariol, Ludivine,Ty, Nancy
-
supporting information
(2020/07/21)
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- COMPOSITIONS AND METHODS FOR DELIVERING A SUBSTANCE TO A BIOLOGICAL TARGET
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The present application provides compositions and methods using bioorthogonal inverse electron demand Diels-Alder cycloaddition reaction for rapid and specific covalent delivery of a payload to a ligand bound to a biological target.
- -
-
Paragraph 0106; 0107
(2020/03/26)
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- Alkene–Azide 1,3-Dipolar Cycloaddition as a Trigger for Ultrashort Peptide Hydrogel Dissolution
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An alkene–azide 1,3-dipolar cycloaddition between trans-cyclooctene (TCO) and an azide-capped hydrogel that promotes rapid gel dissolution is reported. Using an ultrashort aryl azide-capped peptide hydrogel (PhePhe), we have demonstrated proof-of-concept where upon reaction with TCO, the hydrogel undergoes a gel–sol transition via 1,2,3-triazoline degradation and 1,6-self-immolation of the generated aniline. The potential application of this as a general trigger in sustained drug delivery is demonstrated through release of encapsulated cargo (doxorubicin). Administration of TCO resulted in 87 % of the cargo being released in 10 h, compared to 13–14 % in the control gels. This is the first example of a potential bioorthogonal-triggered hydrogel dissolution using a traditional click-type reaction. This type of stimulus could be extended to other aryl azide-capped hydrogels.
- Dadhwal, Sumit,Fairhall, Jessica M.,Goswami, Shailesh K.,Hook, Sarah,Gamble, Allan B.
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supporting information
p. 1143 - 1150
(2018/11/23)
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- Site-Specific Antibody Functionalization Using Tetrazine-Styrene Cycloaddition
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Biologics, such as antibody-drug conjugates, are becoming mainstream therapeutics. Consequently, methods to functionalize biologics without disrupting their native properties are essential for identifying, characterizing, and translating candidate biologics from the bench to clinical practice. Here, we present a method for site-specific, carboxy-terminal modification of single-chain antibody fragments (scFvs). ScFvs displayed on the surface of yeast were isolated and functionalized by combining intein-mediated expressed protein ligation (EPL) with inverse electron-demand Diels-Alder (IEDDA) cycloaddition using a styrene-tetrazine pair. The high thiol concentration required to trigger EPL can hinder the subsequent chemoselective ligation reactions; therefore, the EPL reaction was used to append styrene to the scFv, limiting tetrazine exposure to damaging thiols. Subsequently, the styrene-functionalized scFv was reacted with tetrazine-conjugated compounds in an IEDDA cycloaddition to generate functionalized scFvs that retain their native binding activity. Rapid functionalization of yeast surface-derived scFv in a site-directed manner could find utility in many downstream laboratory and preclinical applications.
- Umlauf, Benjamin J.,Mix, Kalie A.,Grosskopf, Vanessa A.,Raines, Ronald T.,Shusta, Eric V.
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p. 1605 - 1613
(2018/05/14)
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- New multiblock copolymers of norbornene and 5-hydroxycyclooctene
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Cross-metathesis of 5-hydroxycyclooctene and norbornene homopolymers affords the multiblock copolymer possessing a broad range in the degree of blockiness (from 0.03 to 1).
- Denisova, Yulia I.,Gringolts, Maria L.,Roenko, Alexei V.,Shandryuk, Georgiy A.,Finkelshtein, Eugene Sh.,Kudryavtsev, Yaroslav V.
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p. 416 - 418
(2017/08/02)
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- Novel Super-Resolution Imaging Compositions and Methods Using Same
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The invention provides compositions that may be used for imaging intracellular structures. The invention further provides methods of imaging intracellular structures. In certain embodiments, the compositions of the invention include trans-cyclooctene-containing ceramide lipids and tetrazine-containing rhodamine-related dyes.
- -
-
Paragraph 0139
(2016/05/24)
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- Efficient low-cost preparation of trans-cyclooctenes using a simplified flow setup for photoisomerization
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Bioorthogonal ligations have emerged as highly versatile chemical tools for biomedical research. The exceptionally fast reaction between 1,2,4,5-tetrazines and trans-cyclooctenes (TCOs), also known as tetrazine ligation, is frequently used in this regard. Growing numbers of applications for the tetrazine ligation led to an increased demand for TCO compounds, whose commercial availability is still very limited. Reported photochemical procedures for the preparation of TCOs using flow chemistry are straightforward and high yielding but require expensive equipment. Within this contribution, we present the construction and characterization of a low-cost flow photoreactor assembled from readily accessible components. Syntheses of all commonly used trans-cyclooctene derivatives were successfully carried out using the described system. We are convinced that the presented system for photoisomerization will promote access to bioorthogonally reactive TCO derivatives.
- Svatunek, Dennis,Denk, Christoph,Rosecker, Veronika,Sohr, Barbara,Hametner, Christian,Allmaier, Günter,Fr?hlich, Johannes,Mikula, Hannes
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p. 579 - 585
(2016/03/19)
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- Super-resolution imaging of the Golgi in live cells with a bioorthogonal ceramide probe
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We report a lipid-based strategy to visualize Golgi structure and dynamics at super-resolution in live cells. The method is based on two novel reagents: a trans-cyclooctene-containing ceramide lipid (Cer-TCO) and a highly reactive, tetrazine-tagged near-IR dye (SiR-Tz). These reagents assemble via an extremely rapid "tetrazine-click" reaction into Cer-SiR, a highly photostable "vital dye" that enables prolonged live-cell imaging of the Golgi apparatus by 3D confocal and STED microscopy. Cer-SiR is nontoxic at concentrations as high as 2 μM and does not perturb the mobility of Golgi-resident enzymes or the traffic of cargo from the endoplasmic reticulum through the Golgi and to the plasma membrane.
- Erdmann, Roman S.,Takakura, Hideo,Thompson, Alexander D.,Rivera-Molina, Felix,Allgeyer, Edward S.,Bewersdorf, Joerg,Toomre, Derek,Schepartz, Alanna
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supporting information
p. 10242 - 10246
(2015/03/31)
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- UNNATURAL AMINO ACIDS COMPRISING A CYCLOOCTYNYL OR TRANS-CYCLOOCTENYL ANALOG GROUP AND USES THEREOF
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The present invention relates to unnatural amino acids comprising a cyclooctynyl or trans-cyclooctenyl analog group and having formula (I) or an acid or base addition salt thereof. The invention also relates to the use of said unnatural amino acids, kits and processes for preparation of polypeptides that comprise one or more than one cyclooctynyl or trans-cyclooctenyl analog group. These polypeptides can be covalently modified by in vitro or in vivo reaction with compounds comprising an azide, nitrile oxide, nitrone, diazocarbonyl or 1,2,4,5-tetrazine group.
- -
-
Paragraph 0285
(2014/03/25)
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- Compositions And Methods For In Vivo Imaging
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This document relates to compounds useful for targeting PARP1. Also provided herein are methods for using such compounds to detect and image cancer cells.
- -
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Paragraph 0154
(2013/12/03)
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- Preparation of small-molecule microarrays by trans-cyclooctene tetrazine ligation and their application in the high-throughput screening of protein-protein interaction inhibitors of bromodomains
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Fast and efficient: A library of trans-cyclooctene (TCO)-modified small molecules were immobilized on tetrazine-functionalized glass slides by using the fastest bioorthogonal reaction known. The resulting small-molecule microarray was screened against a variety of human bromodomains to identify protein-protein interaction inhibitors. Copyright
- Zhang, Chong-Jing,Tan, Chelsea Y. J.,Ge, Jingyan,Na, Zhenkun,Chen, Grace Y. J.,Uttamchandani, Mahesh,Sun, Hongyan,Yao, Shao Q.
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supporting information
p. 14060 - 14064
(2014/01/06)
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- POST-SYNTHETIC MODIFICATION OF NUCLEIC ACIDS BY INVERSE DIELS-ALDER REACTION
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The present invention concerns a method and a kit for the post-synthetic modification of nucleic acids via an inverse Diels-Alder reaction.
- -
-
Paragraph 0087; 0088; 0089
(2013/04/13)
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- Live-cell imaging of cyclopropene tags with fluorogenic tetrazine cycloadditions
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Spotlight on lipids: One of the major limitations of tetrazine bioorthogonal cycloadditions is the requirement of bulky dienophile reaction partners. Methylcyclopropene tags were designed capable of reacting rapidly with tetrazines while maintaining stability in aqueous solution. The suitability of these probes for bioconjugation is shown by imaging cyclopropene-modified phospholipids in live human cancer cells (see picture). Copyright
- Yang, Jun,?e?kute, Jolita,Cole, Christian M.,Devaraj, Neal K.
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supporting information; scheme or table
p. 7476 - 7479
(2012/09/08)
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- Radical chain reduction of alkylboron compounds with catechols
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The conversion of alkylboranes to the corresponding alkanes is classically per-formed via protonolysis of alkylboranes. This simple reaction requires the use of severe reaction conditions, that is, treatment with a carboxylic acid at high temperature (>150 °C). We report here a mild radical procedure for the transformation of organoboranes to alkanes. 4-tert-Butylcatechol, a well-established radical inhibitor and antioxidant, is acting as a source of hydrogen atoms. An efficient chain reaction is observed due to the exceptional reactivity of phenoxyl radicals toward alkylboranes. The reaction has been applied to a wide range of organoboron derivatives such as B- alkylcatecholboranes, trialkylboranes, pinacolboronates, and alkylboronic acids. Furthermore, the so far elusive rate constants for the hydrogen transfer between secondary alkyl radical and catechol derivatives have been experimentally determined. Interestingly, they are less than 1 order of magnitude slower than that of tin hydride at 80 °C, making catechols particularly attractive for a wide range of transformations involving C-C bond formation.
- Villa, Giorgio,Povie, Guillaume,Renaud, Philippe
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supporting information; experimental part
p. 5913 - 5920
(2011/06/16)
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- Synthesis of a molecular charm bracelet via click cyclization and olefin metathesis clipping
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We describe the synthesis of a polycatenated cyclic polymer, a structure that resembles a molecular charm bracelet. Ruthenium-catalyzed ring-opening metathesis polymerization of an aminocontaining cyclic olefin monomer in the presence of a chain transfer agent generated an α,ω-diazide functionalized polyamine. Cyclization of the resulting linear polyamine using pseudo-high-dilution coppercatalyzed click cyclization produced a cyclic polymer in 19% yield. The click reaction was then further employed to remove linear contaminants from the cyclic polymer using azide- and alkyne-functionalized scavenging resins, and the purified cyclic polymer product was characterized by gel permeation chromatography, 1H NMR spectroscopy, and IR spectroscopy. Polymer hydrogenation and conversion to the corresponding polyammonium species enabled coordination and interlocking of diolefin polyether fragments around the cyclic polymer backbone using ruthenium-catalyzed ring-closing olefin metathesis to afford a molecular charm bracelet structure. This charm bracelet complex was characterized by 1H NMR spectroscopy, and the catenated nature of the small rings was confirmed using two-dimensional diffusionordered NMR spectroscopy.
- Clark, Paul G.,Guidry, Erin N.,Chan, Wing Yan,Steinmetz, Wayne E.,Grubbs, Robert H.
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supporting information; experimental part
p. 3405 - 3412
(2010/05/01)
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- TETRAZINE-BASED BIO-ORTHOGONAL COUPLING REAGENTS AND METHODS
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Coupling reactions, suitable for use in organic or aqueous media, are performed by contacting a 1,2,4,5-tetrazine with a dienophile. The dienophile may be covalently bonded to a protein, and the coupling reaction may be performed in biological media such as those containing cells or cell lysates. The reactions may be performed in the presence of primary amines, thiols, acetylenes, azides, phosphines, and products of Staudinger and/or Sharpless-Huisgen reactions Novel 3-substituted cyclopropene compounds and trans-cyclooctenes are exemplary dienophiles for these reactions.
- -
-
Page/Page column 15
(2009/02/11)
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- Synthesis of pendent functionalized cyclotriphosphazene polyoctenamers: Amphiphilic lithium ion conductive materials
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The synthesis of novel polyoctenamers with pendent functionalized cyclotriphosphazenes as amphiphilic lithium ion conductive membranes is described. Cyclotriphosphazene monomers were functionalized with one cycloocteneoxy substituent per ring. Two different types of monomer units, one with oligoethyleneoxy cation coordination side groups and the other with hydrophobic fluoroalkoxy side groups, were then prepared. The syntheses of these monomers, their ring-opening metathesis copolymerization, and the characteristics of the resultant polymers are discussed, with an emphasis on the dependence of ionic conductivity and hydrophobicity on polymer composition.
- Allcock, Harry R.,Welna, Daniel T.,Stone, David A.
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p. 10406 - 10412
(2008/02/01)
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- Synthesis of fluorinated cycloalkyl N-phenylcarbamates and their microbial defluorination/oxygenation by Beauveria bassiana
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Earlier investigations showed that cycloalkyl N-phenylcarbamates were hydroxylated by the fungus Beauveria bassiana predominantly in the 4-position relative to the electron-rich substituent. In cases involving fluorinated methylene groups potentially capable of hydroxylation, however, defluorination and formation of a ketone was observed. The formation of the ketone can be explained by primary hydroxylation to forman unstable geminal fluorohydrin, which is subsequently dehydrofluorinated. Wiley-VCH Verlag GmbH & Co. KGaAA, 69451 Weinheim, Germany, 2003.
- Haufe, Guenter,Pietz, Sylke,Woelker, Doerthe,Froehlich, Roland
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p. 2166 - 2175
(2007/10/03)
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- Highly chemoselective catalytic hydrogenation of unsaturated ketones and aldehydes to unsaturated alcohols using phosphine-stabilized copper(I) hydride complexes
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A base metal hydrogenation catalyst composed of the phenyldimethylphosphine-stabilized copper(I) hydride complex provides for the highly chemoselective hydrogenation of unsaturated ketones and aldehydes to unsaturated alcohols, including the regioselective 1,2-reduction of α,β- unsaturated ketones and aldehydes to allylic alcohols. The active catalyst can be derived in situ by phosphine exchange using commercial [(Ph3P)CuH]6 or from the reaction of copper(l) chloride, sodium tert-butoxide, and dimethylphenylphosphine under hydrogen. The catalyst derived from 1,1,1- tris(diphenylphosphinomethyl)ethane is mechanistically interesting but less synthetically useful. (C) 2000 Elsevier Science Ltd.
- Chen, Jian-Xin,Daeuble, John F.,Brestensky, Donna M.,Stryker, Jeffrey M.
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p. 2153 - 2166
(2007/10/03)
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- Design and synthesis of violet odorants with bicyclo[6.4.0]dodecene and bicyclo[5.4.0]undecene skeletons
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The Diels-Alder reaction of 1,2-bis(methylene)cyclooctane (13), 4- methylenespiro[2.7]decane (29), 4-methylenespiro[2.6]nonane (40) and 4- methylenespiro[2.7]dec-8-ene (46) with different α,β-unsaturated carbonyl compounds afforded various derivatives 16, 18, 20, 22, 24, 26, 32, 36, 38, 41, 42 and 47 of a molecular-modeled lead compound 9. These less flexible β- ionone-mimics with bicyclo[6.4.0]dodecene and bicyclo[5.4.0]undecene skeletons possess interesting fruity-woody-floral odor notes and provide insight into the structure-odor correlation of violet odorants. 5-(2- Methylcycloalk-1-en-1-yl)hex-3-en-2-ones (e.g. 35) were identified as byproducts of the Rh(I)-catalyzed reactions of the vinylcyclopropanes 29 and 40.
- Kraft, Philip
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p. 695 - 703
(2007/10/03)
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- Ring-fused and spiro cyclopentenones by Ni(CO)4-promoted intermolecular carbonylative cycloaddition of acetylenes with 3-halo- and 1-(halomethyl)cycloalkenes
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The title carbonylative cycloaddition of five- to eight-member ring 3-halo- and 1-(halomethyl)cycloalkenes with different acetylenes was studied. From moderate to good yields of ring-fused and spiro cyclopentenone derivatives were obtained, especially in the reaction with acetylenes bearing electron-withdrawing substituents by proper selection of the reaction conditions to avoid the acetylene polyinsertion and/or other side reactions from the organonickel intermediates. In this context, the beneficial role of acetate ion on the outcome of the reaction is rationalized. This process leading to the formation of bicycloadducts with the concomitant formation of up to six C-C bonds, with high regio- and stereoselectivity, can be useful in the synthesis of natural products as exemplified by the easy preparation of [5-5-5] tricyclic compound 14 from a 1:1 cis and trans isomeric mixture of 6-acetoxy-3-bromocyclooctene (11). A plausible general reaction mechanism is proposed that is consistent with all the products obtained.
- Pagès, Lluís,Llebaria, Amadeu,Camps, Francisco,Molins, Elies,Miravitlles, Caries,Moretó, Josep M.
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p. 10449 - 10461
(2007/10/02)
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- Preparation of Unsaturated Hydroperoxides from N-Alkenyl-N'-p-tosylhydrazines
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Unsaturated hydroperoxides (R1R2CHO2H), 2-phenylpent-4-enyl hydroperoxide (1), 3-phenylhex-5-en-2-yl hydroperoxide (2), 5-methylhex-5-en-2-yl hydroperoxide (3), cyclo-oct-4-enyl hydroperoxide (18), and cyclo-oct-3-enyl hydroperoxide (24) have each been prepared from the corresponding carbonyl compound (R1R2CO) by the sequence: i, conversion to the p-tosylhydrazone (R1R2C=N-NHTs); ii, reduction with sodium cyanoborohydride at pH 3.5 to give the N'-p-tosylhydrazine (R1R2CH-NH-NHTs); and iii, oxidation with hydrogen peroxide and sodium peroxide.Isomerisation occurs in the preparation of the cyclo-octenyl hydroperoxides, particuarly if the pH falls markedly below 3.5 in the reduction step.
- Bloodworth, A. J.,Courtneidge, J. L.,Curtis, Richard J.,Spencer, Michael D.
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p. 2951 - 2955
(2007/10/02)
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- Synthesis of 9-Oxabicyclonon-3-yne
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Starting with 1,5-cyclooctadiene (1), the title compound 9 is gained in a synthesis of seven steps. 9 exists in two conformations 9a and 9b, of which 9a shows a strong interaction between the oxygen atom and the strained triple bond.Thermal fragmentation of the 1,2,3-selenadiazole 7 is used for the introduction of the triple bond.The structural proof of 7 is performed by 2D-NMR spectroscopy.
- Meier, Herbert,Mayer, Winfried,Kolshorn, Heinz
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p. 685 - 690
(2007/10/02)
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- Displacement Stereochemistry and Product-Formation Selectivities in the Solvolysis of Cyclooctyl p-Bromobenzenesulfonate
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Configurational analysis by 2H NMR of the products of solvolysis of (E)-cyclooctyl-2-d and (E)-cyclooctyl-4-d brosylate in acetic acid and 80percent acetone has established that substitution without rearrangement occurs with complete retention of configuration while substitution under 1,5-hydride shift takes place with complete inversion at the migration origin.The reaction is concluded to proceed by direct initial formation of a 1,5-hydrogen-bridged cation.Solvolysis of cyclooctyl-1-d brosylate in several solvents has shown elimination to be favored from C-1 over the C-5 side, whereas selectivities for competitive substitutions are similar at the two positions.Elimination is thus indicated to take place largely from first-formed tight ion pairs while displacement proceeds through more dissociated intermediates.
- Nordlander, J. Eric,Owuor, Philip O.,Cabral, Donna J.,Haky, Jerome E.
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p. 201 - 206
(2007/10/02)
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- CYCLIC α,β-EPOXYSILANES ACID-CATALYSED REACTIONS OF 1-TRIMETHYLSILYLCYCLOOCTENE OXIDE
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The acid-catalysed reactions of medium ring α,β-epoxysilane 1 are described.The epoxide 1 gives exclusively the bicyclic alcohol 2 with boron trifluoride etherate.With aqueous sulphuric acid the products are due to both transannular ring closure, 2, and transannular hydride migration, 3 and 4. trans-Cyclooctene derivatives 3 and 4 are formed by the trans-elimination of trimethylsilanol from the likely intermediate β-hydroxysilanes 10 and 11.The results with methanolic sulphuric acid are similar.It is also noticed that the hydride migration is facilitated by the nucleophilic strength of the medium.
- Nagendrappa, Gopalpur
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p. 2429 - 2434
(2007/10/02)
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- Vinyl-Kationen, 32 Solvolysereaktionen von Cyclononinyl- und Cyclooctinylderivaten
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5-Cyclononyn-1-yl 4-nitrobenzoate (11), 4-cyclononyn-1-yl 4-nitrobenzoate (12), and 4-cyclooctyn-1-yl 4-nitrobenzoate (13) were synthesized and their solvolysis reactions in different solvent systems were studied. 11 rearrranges on solvolysis in 50percent ethanol practically quantitatively by transanular participation of the triple bond via the vinyl cation intermediate 20 to give bicyclononan-2-one (21).On the other hand the 4-nitrobenzoates 12 and 13 solvolyse without transanular reaction, in spite of the spatial nearness between triple bond and functional C-atom.This shows that under the solvolytic conditions the strained bicyclic vinyl cations 29-32 were not formed as intermediates.
- Hanack, Michael,Spang, Werner
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p. 2015 - 2024
(2007/10/02)
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- Studies on the Autoxidation of Some Monocyclic Olefins
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The autoxidations of cyclopentene, cyclohexene, cycloheptene, cyclooctene, cycloocta-1,5-diene, 1-methylcyclopentene, 1-methylcyclohexene, 1-methylcycloheptene, 1-methylcyclooctene, methylene cyclopentene, and methylene cyclohexene with pure oxygen under normal pressure were studied.The epoxides formed were determined gaschromatographically.In most cases also the products of allylic oxidation were analyzed and their structures elucidated after reduction to the corresponding allyl alcohols.The portions of high boiling or polymeric products which could not be detected gaschromatographically and also the real yields of epoxides were determined by balance experiments in the presence of inert internal standards.
- Blau, K.,Mueller, U.,Pritzkow, W.,Schmidt-Renner, W.,Sedshaw, Z.
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p. 915 - 932
(2007/10/02)
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