- New SF5-long chain carbon systems
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A new SF5-terminated perfluoroalkyl thiol - SF5(CF2)6CH2CH2SH - and a symmetric SF5-terminated dialkyl disulfide - [SF5CH-CH(CH2)8S]2 - were synthesized from the corresponding SF5-terminated precursors. The chemistry employed in the preparation of the disulfide encompasses high yield pathways for the preparation of new SF5-long chain derivatives.
- Winter,Nixon,Gard,Radford,Holcomb,Grainger
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Read Online
- Evaluation of gem-Diacetates as Alternative Reagents for Enzymatic Regio-and Stereoselective Acylation of Alcohols
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Geminal diacetates have been used as sustainable acyl donors for enzymatic acylation of chiral and nonchiral alcohols. Especially, it was revealed that geminal diacetates showed higher reactivity than vinyl acetate for hydrolases that are sensitive to acetaldehyde. Under optimized conditions for enzymatic acylation, several synthetically relevant saturated and unsaturated acetates of various primary alcohols were obtained in very high yields up to 98% without E/Z isomerization of the double bond. Subsequently, the acyl donor was recreated from the resulting aldehyde and reused constantly in acylation. Therefore, the developed process is characterized by high atomic efficiency. Moreover, it was shown that acylation using geminal diacetates resulted in remarkable regioselectivity by discriminating among the primary and secondary hydroxyl groups in 1-phenyl-1,3-propanediol providing exclusively 3-acetoxy-1-phenyl-propan-1-ol in good yield. Further, enzymatic kinetic resolution (EKR) and chemoenzymatic dynamic kinetic resolution (DKR) protocols were developed using geminal diacetate as an acylating agent, resulting in chiral acetates in high yields up to 94% with enantiomeric excesses exceeding 99%.
- Koszelewski, Dominik,Brodzka, Anna,Madej, Arleta,Trzepizur, Damian,Ostaszewski, Ryszard
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p. 6331 - 6342
(2021/05/06)
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- Amine-borane complex-initiated SF5Cl radical addition on alkenes and alkynes
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The SF5Cl radical addition on unsaturated compounds was performed using an air-stable amine-borane complex as the radical initiator. This method showed to be complementary to the classic Et3B-mediated SF5Cl addition on alkenes and alkynes. A total of seven alkene and three alkyne derivatives were tested in the reaction, with yields ranging from 3% to 85%.
- Gilbert, Audrey,Langowski, Pauline,Delgado, Marine,Chabaud, Laurent,Pucheault, Mathieu,Paquin, Jean-Fran?ois
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supporting information
p. 3069 - 3077
(2021/01/15)
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- PRODUCTION OF FATTY OLEFIN DERIVATIVES VIA OLEFIN METATHESIS
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In one aspect, the invention provides a method for synthesizing a fatty olefin derivative. The method includes: a) contacting an olefin according to Formula I with a metathesis reaction partner according to Formula IIb in the presence of a metathesis catalyst under conditions sufficient to form a metathesis product according to Formula IIIb: and b) converting the metathesis product to the fatty olefin derivative. Each R1 is independently selected from H, C1-18 alkyl, and C2-18 alkenyl; R2b is C1-8 alkyl; subscript y is an integer ranging from 0 to 17; and subscript z is an integer ranging from 0 to 17. In certain embodiments, the metathesis catalyst is a tungsten catalyst or a molybdenum catalyst. In various embodiments, the fatty olefin derivative is a pheromone. Pheromone compositions and methods of using them are also described.
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- Ethyl acetate as an acetyl surrogate for the iodine catalyzed acetylation of alcohols
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The use of readily available ethyl acetate in the presence of iodine as an alternative acetylating agent is reported. Amines and phenols were unreactive under the examined reaction conditions, indicating that the method is highly chemoselective.
- Basumatary, Grace,Bez, Ghanashyam
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supporting information
p. 4312 - 4315
(2017/10/13)
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- Nucleoside analogues with a 1,3-diene-Fe(CO)3 substructure: Stereoselective synthesis, configurational assignment, and apoptosis-inducing activity
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The synthesis and stereochemical assignment of two classes of iron-containing nucleoside analogues, both of which contain a butadiene-Fe(CO)3 substructure, is described. The first type of compounds are Fe(CO)3-complexed 3'-alkenyl-2′,3′-dideoxy- 2′,3′-dehydro nucleosides (2,5-dihydrofuran derivatives), from which the second class of compounds is derived by formal replacement of the ring oxygen atom by a CH2 group (carbocyclic nucleoside analogues). These compounds were prepared in a stereoselective manner through the metal-assisted introduction of the nucleobase. Whilst the furanoid intermediates were prepared from carbohydrates (such as methyl-glucopyranoside), the carbocyclic compounds were obtained by using an intramolecular Pauson-Khand reaction. Stereochemical assignments based on NMR and CD spectroscopy were confirmed by X-ray structural analysis. Biological investigations revealed that several of the complexes exhibited pronounced apoptosis-inducing properties (through an unusual caspase 3-independent but ROS-dependent pathway). Furthermore, some structure-activity relationships were identified, also as a precondition for the design and synthesis of fluorescent and biotin-labeled conjugates. I gotta Fe-ling: Iron-containing nucleoside analogues, which were first synthesized during an exercise in stereoselective π-complex chemistry, exhibited pronounced cytotoxic and apoptosis-inducing activities, even against resistant cancer cell lines. Both hetero- (X=O) and carbocyclic (X=CH2) compounds were studied, and a synthetic route to R′-labeled derivatives was developed as a precondition for future biological experiments. TDS=thexyldimethylsilyl. Copyright
- Hirschh?user, Christoph,Velcicky, Juraj,Schlawe, Daniel,Hessler, Erik,Majdalani, André,Neud?rfl, J?rg-Martin,Prokop, Aram,Wieder, Thomas,Schmalz, Hans-Günther
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supporting information
p. 13017 - 13029
(2013/10/01)
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- Synthetic route discovery and introductory optimization of a novel process to idebenone
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An environmentally benign, convenient, high yielding, and cost-effective synthesis leading to idebenone is disclosed. The synthesis includes a bromination process for the preparation of 2-bromo-3,4,5-trimethoxy-1- methylbenzene, a protocol for the Heck cross-coupling reaction using either thermal or microwave heating, olefin reduction by palladium catalyzed hydrogenation, and a green oxidation protocol with hydrogen peroxide as oxidant to achieve the benzoquinone framework. The total synthesis is composed of six steps that provide an overall yield of 20% that corresponds to a step yield of 76%.
- Tsoukala, Anna,Bjorsvik, Hans-Rene
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p. 673 - 680
(2011/12/01)
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- Locking out ants - Synthesis and biological evaluation of some fluorinated repellents
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We synthesized a series of fluorinated compounds and tested them in an easy assay for their repellent activity against the ant Myrmica rubra. Depending on their chain length and pattern of fluorination these molecules are efficient repellents for this ant. Fluorinated compounds are stronger repellents than their unfluorinated analogs. 1,1,1-Trifluorotridecan-2-one (4) is an even better repellent against M. rubra than "gold standard" N,N-diethyl-m- toluamide (DEET).
- Csuk, Rene,Tamba, Maria Gabriela,Kluge, Ralph
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experimental part
p. 1069 - 1075
(2011/12/13)
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- Enantioselective synthesis of α-alkyl-β,γ-unsaturated esters through efficient Cu-catalyzed allylic alkylations
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Treatment of an (allyl)organosilane with silica gel in refluxing toluene brought about deallylation forming an Si-O-Si bond with the silicon on the silica gel. This Si-O-Si bond formation provides us with a new reliable method for the functionalization of a silica gel surface. Copyright
- Murphy, Kerry E.,Hoveyda, Amir H.
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p. 4690 - 4691
(2007/10/03)
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- Osmium tetroxide-promoted catalytic oxidative cleavage of olefins: An organometallic ozonolysis
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A mild, organometallic alternative to ozonolysis utilizing oxone and OsO4 is presented. This is a direct oxidation of olefins via the carbon-carbon cleavage of an osmate ester by the action of oxone. Twenty-four different olefins were converted to their corresponding ketones or carboxylic acids in high yields (> 80%). Free alcohols, acetate- and benzyl-protected alcohols, and 1,2-diols were stable under these conditions. This method should be applicable for traditional organic synthesis. Copyright
- Travis, Benjamin R.,Narayan, Radha S.,Borhan, Babak
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p. 3824 - 3825
(2007/10/03)
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- A versatile approach to the synthesis of 9(Z)-unsaturated acyclic insect pheromones from undec-10-enoic acid
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A general approach to the synthesis of 9(Z)-unsaturated acyclic insect pheromones from undec-10-enoic acid was developed. The method comprises the conversion of the acid into undec-10-enyl acetate, shortening of its carbon chain to afford dec-9-enyl acetate (via 11-acetoxyundecanoic acid), and a two-step transformation of the latter into the key intermediate, dec-9-yn-1-ol, by sequential bromination - dehydrobromination. The elimination of two HBr molecules from the dibromide is effectively performed using Bu1OK in the presence of dibenzo-18-crown-6 as the catalyst.
- Ishmuratov,Kharisov,Yakovleva,Botsman,Galeeva,Ishmuratova,Tolstikov
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p. 1595 - 1597
(2007/10/03)
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- Zeolite HSZ-360 as a new reusable catalyst for the direct acetylation of alcohols and phenols under solventless conditions
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Alcohols and phenols were efficiently acylated with acetic anhydride without solvent over zeolite HSZ-360. The catalyst can be reused with no activity loss.
- Ballini, Roberto,Bosica, Giovanna,Carloni, Silvia,Ciaralli, Lara,Maggi, Raimondo,Sartori, Giovanni
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p. 6049 - 6052
(2007/10/03)
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- Synthesis of succinic diesters via reductive coupling of α-haloesters using samarium(II) iodide and HMPA
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Primary and secondary α-haloesters are converted to succinic diesters in good yield by treatment with SmI2-HMPA.
- Balaux,Ruel
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p. 801 - 804
(2007/10/03)
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- Pesticidal polyhalo alkenoic acid esters
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The present invention discloses and exemplifies alcohol, ether and ester derivatives of difluoroalkanes and difluoroalkenylalkanes having the general formula R--(CH2)m --CR2 R3 --OR1, in which R is a 1,1-difluoroalkyl or a 1,1-difluoroalkenyl group, composition thereof, and use thereof to control agricultural crop pests.
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- A spacer-modified disaccharide as a photoaffinity reagent for the acceptor-binding area of bovine (1->4)-β-D-galactosyltransferase: comparison of its acceptor properties with those of other 2-acetamido-2-deoxy-β-D-glucopyranosides
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The spacer-modified disaccharide 1,10-di-O-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-2-azi-1,10-decanediol (10) that mimics the biantennary core heptasaccharide of N-glycoproteins has been synthesised.Compound 10 is an excellent acceptor in galactosyltransferase-catalysed galactosylation by UDP-galactose, is superior (7-8 fold) to analogues that have only one GlcNAc unit, and is an efficient photoaffinity reagent for galactosyltransferase.In the presence of UDP-Gal, no photoaffinity labelling by 10 takes place, which agrees with the mechanism of galactosyltransferase action.
- Ats, Sandor-Csaba,Lehmann, Jochen,Petry, Stefan
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p. 125 - 139
(2007/10/02)
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- MILD PROTECTION AND DEPROTECTION OF ALCOHOLS AS TER-BUTYL ETHERS IN THE FIELD OF PHEROMONE SYNTHESIS
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α,ο-Halohydrins and ο-acetylenic alcohols are protected as t-butyl ethers by reaction with isobutene and an acid catalyst : Amberlyst H-15. t-Butyl ethers are, in turn, cleaved to acetates by Ac2O and 10 percent FeCl3 in Et2O solvent.Under these mild conditions conjugated dieneic systems are neither destroyed nor isomerized.
- Alexakis, A.,Gardette, M.,Colin, S.
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p. 2951 - 2954
(2007/10/02)
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- Vinylic Organoboranes. 3. Pheromones via Organoboranes. 1. Stereospecific Synthesis of Straight-Chain Z-Monoolefinic Insect Pheromones via Lithium (1-Alkynyl)trialkylborates
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Various insect pheromones with straight-chain Z-monoolefinic structures have been prepared from lithium (1-alkynyl)trialkylborates.Treatment of lithium (1-alkynyl)trialkylborates, readily prepared from lithium acetylides and trialkylboranes, with iodine under mild conditions produces the corresponding alkynes in essentially quantitative yield.Monohydroboration of the resultant alkyne with 9-borabicyclononane yields the corresponding (Z)-olefin after protonolysis.The combination of these two reaction sequences provides a general route for the synthesis of (Z)-olefins.The position of the double bond and the carbon-chain length are easily controlled by properly choosing the initial reactants.The incorporation of functional groups is also easily achieved because of the mild reaction conditions and the tolerance of hydroboration to many functional groups.High yield and purity of the products are obtained.
- Brown, Herbert C.,Wang, Kung K.
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p. 4514 - 4517
(2007/10/02)
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- ALKENYL COPPER REAGENTS-26 CARBOCUPRATION OF ALKYNES BY ORGANOCOPPER REAGENTS BEARING A PROTECTED HYDROXY OR THIOL FUNCTION
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Halohydrins, protected as ethers, acetals or chloro-magnesium alcoholates are sequentially transformed into the Li or Mg reagents and then into copper or cuprate derivatives.Addition to acetylene or propyne is discussed according to various parameters.The alkenyl copper or cuprate species, thus obtained, may react further with various electrophiles, leading to difunctionalized alkenes.
- Gardette, M.,Alexakis, A.,Normant, J. F.
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p. 5887 - 5900
(2007/10/02)
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- BAEYER-VILLIGER OXIDATION WITH Me3SiOOSiMe3 UNDER ASSISTANCE OF SnCl4 OR BF3-OEt2.
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Treatment of ketones with bis(trimethylsilyl) peroxide and Lewis acid such as SnCl//4 or BF//3-OEt//2 in dichloromethane at room temperature affords esters in fair to excellent yields. Jasmine lactone is synthesized from 2- left bracket (Z)-pentenyl right bracket cyclopentanine by means of Me//3SiOOSiMe//3-BF//3-OEt//2 system without any protection of the carbon-carbon double bond. The oxidation of enol acetates of ketones to alpha -hydroxy (or alpha -acetoxy) ketones with Me//3SiOOSiMe//3-FeCl//3 system is also disclosed.
- Matsubara,Takai,Nozaki
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p. 2029 - 2032
(2007/10/02)
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- ORGANO-CUIVREUX VINYLIQUES 17. CARBOCUPRATION D'ALCYNES PAR DES ORGANO-CUPRATES ET -CUIVREUX FONCTIONNELS
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Some organocopper and cuprate derivatives, distally bearing a free or protected hydroxyl group, add to alkynes, to give α,ο-bifunctional olefins.
- Gardette, M.,Alexakis, A.,Normant, J. F.
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p. 5155 - 5158
(2007/10/02)
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- Synthesis of Methyl Esters by Titanate-catalyzed Transesterifications
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The low solubility of tetramethyl titanate has so far prevented the laboratory use of titanate-catalyzed transesterifications with formation of methyl esters.Two procedures are described here, which allow the application of this exceedingly mild method to the synthesis of methyl esters: one uses methyl propionate/Ti(OEt)4, the other one uses methanol/Gly-Ti, a new type of catalyst, prepared from Ti(OEt)4/ethylene glycol 2:1.
- Schnurrenberger, Peter,Zueger, Max F.,Seebach, Dietrich
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p. 1197 - 1201
(2007/10/02)
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- METATHESE D'ACETATES D'ALCOOLS ω-INSATURES. SYNTHESE DE PHEROMONES D'INSECTES
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Esters of alkenoic acids, including insect pheromones as examples, have been synthesized using alkene metathesis reactions.
- Levisalles, Jaques,Villemin, Didier
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p. 3181 - 3186
(2007/10/02)
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