- Immobilization of biomolecules via ruthenium-catalyzed functionalization of the surface of silica with a vinylsilane
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A new ruthenium complex catalyzed procedure for the efficient O-silylation of an SiO-H group on the silica surface of glass beads with controlled pores (CPG) using 1-trimethylsiloxy-3-dimethylvinylsilylpropane leading to Si-O-Si bond formation with the evolution of ethylene is described. The formed linker contains alkyl hydroxyl groups which can be reacted with a nucleoside phosphoramidite unit. The CPG support containing alkyl hydroxyl groups is successfully applied in automatic chemical synthesis of DNA fragments.
- Hreczycho, Grzegorz,Chmielewski, Marcin K.,MacIejewski, Hieronim,Ratajczak, Tomasz,Marciniec, Bogdan
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Read Online
- Synthesis of bifunctional disiloxanes: Via subsequent hydrosilylation of alkenes and alkynes
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The first protocol for the synthesis of unsymmetrical bifunctional 1,1,3,3-tetramethyldisiloxane derivatives via subsequent hydrosilylation of alkenes and alkynes is presented. The methodology described has vast functional group tolerance and is extremely efficient towards the formation of novel disiloxane-based building blocks.
- Szyling, Jakub,Januszewski, Rafa?,Jankowska, Kamila,Walkowiak, J?drzej,Kownacki, Ireneusz,Franczyk, Adrian
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Read Online
- Synthesis and photophysical properties of a new BODIPY-based siloxane dye
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A fluorescent dye comprising four BODIPY derivatives conjugated to a cyclotetrasiloxane core was synthesized by consecutive hydrosilylation and esterification reactions. Photophysical properties of the dye in various organic solvents were investigated. It was shown that due to a fourfold extinction coefficient increase and a moderate quantum yield decrease the brightness of the tetra-BODIPY dye in low-polarity solvents, calculated per molecule, increased 3 times when compared to mono-BODIPY. By contrast, in polar solvents there was a dramatic drop in brightness apparently associated with intramolecular interactions of the low-polar BODIPY chromophores.
- Pakhomov, Alexey A.,Kononevich, Yuriy N.,Stukalova, Maria V.,Svidchenko, Evgeniya A.,Surin, Nikolay M.,Cherkaev, Georgy V.,Shchegolikhina, Olga I.,Martynov, Vladimir I.,Muzafarov, Aziz M.
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supporting information
p. 979 - 982
(2016/02/18)
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- Microwave-assisted synthesis of 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane
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1,3-Bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane was synthesized under microwave irradiation. The structure of the compound was analyzed by infrared spectroscopy, nuclear magnetic resonance hydrogen spectroscopy and gas chromatography. The optimal reaction condition was obtained by the single factor method. Under the optimal condition, the overall yield could reach 83.9 % and the purity of 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane was 99.1 %. It is found that under microwave radiation the reactions are very rapid with good yield, better quality and less time is required for the completion of the reaction.
- Cheng, Xitao,Li, Wenhong,Zhang, Cunshe,Huang, Fangfang,Wang, Qianjin,Zhou, Kui
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p. 567 - 571
(2016/01/20)
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- FUNCTIONALIZED SILANES AND ELECTROLYTE COMPOSITIONS AND ELECTROCHEMICAL DEVICES CONTAINING THEM
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Described are compounds of the structure R4-a-Si-(Sp-Y)a-Zb, wherein "a" is integer from 1 to 4; "b" is an integer from 0 to (3 x a); "Z," which is absent when "b "R" or formula (II), wherein each "R" is halogen, C1-6 linear or branched alkyl, alkenyl, or alkynyl or C1-6 linear or branched halo-alkyl, halo-alkenyl, or halo-alkynyl; each "Sp" C1-15 linear or branched alkylenyl or CMS linear or branched halo-alkylenyl; and each "Y" an organic polar group. Also described are electrolyte compositions containing one or more of these compounds.
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Page/Page column 28
(2016/04/26)
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- A 2 - ((4R, 6S) - 6-substituted methyl-2-substituent -1,3-dioxane-4-yl) acetate preparation method
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The invention relates to a method for preparing 2-((4R, 6S)-6-substituted methyl-2-substituent group-1,3-dioxane-4-yl) acetate. The method comprises the following steps: by utilizing substituted ethylene and 3,3-dialkoxy propionate or 3-alkoxy acrylate, preparing 2-((4R, 6S)-6-substituted methyl-2-ester group methyl-1,3-dioxane-4-yl) acetate under catalysis of a Lewis acid; and preparing ethyl 2-((4R, 6S)-6-chloromethyl-2-substituted phenyl-1,3-dioxane-4-yl) acetate through hydrolysis ring opening and ring formation protection, performing hydrolysis ring opening again, performing ring formation protection with a carbonyl compound X or glycol XI thereof, and thus obtaining 2-((4R, 6S)-6-substituted methyl-2-substituent group-1,3-dioxane-4-yl) acetate. A chiral center is established by utilizing an equatorial bond stable form of a six-membered ring chair structure, and a chiral auxiliary reagent is not additionally used. The raw materials are readily available, the reaction process is short, asymmetric reduction of carbonyl is avoided, flammable and combustible reducing agents are not used, and the preparation method is easy, convenient, environment-friendly and suitable for large-scale industrial production.
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Paragraph 0070; 0071
(2017/02/24)
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- Room-Temperature Gold-Catalysed Arylation of Heteroarenes: Complementarity to Palladium Catalysis
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Tailoring of the pre-catalyst, the oxidant and the arylsilane enables the first room-temperature, gold-catalysed, innate C?H arylation of heteroarenes. Regioselectivity is consistently high and, in some cases, distinct from that reported with palladium ca
- Cresswell, Alexander J.,Lloyd-Jones, Guy C.
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supporting information
p. 12641 - 12645
(2016/08/30)
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- Preparation of nano silica supported sodium hydrogen sulfate: As an efficient catalyst for the trimethyl, triethyl and t-butyldimethyl silylations of aliphatic and aromatic alcohols in solution and under solvent-free conditions
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Nano silica supported sodium hydrogen sulfate has been prepared by mixing NaHSO4 with activated Nano silicagel. We wish to report a new method for the synthesis of trimethyl (TMS), triethyl (TES) and t-butyldimethyl silyl (TBS) ethers from benzylic, allylic, propargylic alcohols, phenols, naphtholes and some of phenolic drugs in the solution and under solvent-free conditions.
- Abri, Abdolreza,Ranjdar, Somayeh
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p. 929 - 934
(2014/10/16)
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- Polystyrene-gallium trichloride complex: A mild, highly efficient, and recyclable polymeric lewis acid catalyst for chemoselective silylation of alcohols and phenols with hexamethyldisilazane
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Polystyrene-supported gallium trichloride (PS/GaCl3) as a highly active and reusable heterogeneous Lewis acid effectively activates hexamethyldisilazane (HMDS) for the efficient silylation of alcohols and phenols at room temperature. In this he
- Rahmatpour, Ali,Vakili, Ali,Azizian, Setare
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p. 443 - 451
(2013/12/04)
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- Synthesis of acylsilanes via nickel-catalyzed reactions of α-hydroxyallylsilanes
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The redox isomerization processes and tandem isomerization-aldolization reactions, mediated by nickel catalysts, offer new versatile entries to acylsilanes. For the second reaction, high diastereoselectivities, up to 98:2, have been obtained with bulky substituents on silicon.
- Reddy, Gangireddy PavanKumar,Reddy, J. Satyanarayana,Das, Saibal,Roisnel, Thierry,Yadav, Jhillu S.,Chandrasekhar, Srivari,Gree, Rene
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supporting information
p. 1524 - 1527
(2013/06/27)
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- A mild and highly efficient method for the preparation of silyl ethers using Fe(HSO4)3/Et3N by chlorosilanes
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Avery efficient and mild procedure for preparation of silyl ethers from benzylic, allylic, propargilic alcohols, phenols, naphtoles and some of phenolic drugs with trimethylsilylchloride (TMSCl), triethylsilylchloride (TESCl) and t-buthyldimethylsilyl chloride (TDSCl) ethers in the presence of Fe(HSO 4)3/Et3N in roomtemperature in excellent yields is reported. This procedure also allows the excellent selectivity for silylation of alcohols and phenols.
- Abri, Abdolreza,Assadi, Mohammad Galeh,Pourreza, Samira
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p. 1449 - 1454
(2013/03/13)
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- Synthesis and characterization of some bis(hydroxyalkyl)- and bis(hydroxyester)-functionalized disiloxanes
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Novel hydroxyester disiloxanes (1,3-bis(6-hydroxyhexa noylmethyl)-1,1,3,3- tetramethyl disiloxane and 3-bis(2-hydroxypropanoylmethyl)tetramethyl disiloxane) were synthesized, and preparation of other known monomers, namely 1,3-bis(hydroxypropyl)-1,1,3,3-tetramethyl disiloxane, 1,3- bis(hydroxyethoxypropyl)-1,1,3,3-tetramethyl disiloxane and 1,3- bis(hydroxymethyl)-1,1,3,3-tetramethyl disiloxane was developed to obtain better yields and reduce production time and expense. All compounds were characterized by infrared spectroscopy, using 1H NMR, 13C NMR, and 29Si NMR and were reacted with diisocyanates, resulting in poly(siloxane-urethane) copolymers with unique properties.
- Pusztai, Erika,Nagy, Jozsef,Wagner, Oedoen
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- Tetrabutylammonium phthalimide-N-oxyl: An efficient organocatalyst for trimethylsilylation of alcohols and phenols with hexamethyldisilazane
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Tetrabutylammonium phthalimide-N-oxyl (TBAPINO) was found to be an effective organocatalyst for rapid, simple and chemoselective protection of the hydroxyl group of alcohols and phenols using hexamethyldisilazane (HMDS) under mild conditions. The low catalyst loading, high to quantitative yields and simple removal of the catalyst from the reaction mixture illustrate the other attractive features of this protocol.
- Dekamin,Yazdaninia,Mokhtari,Naimi-Jamal
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experimental part
p. 537 - 544
(2012/06/18)
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- An expeditious, efficient green methodology for the Boc protection of amines and silyl protection of alcohols over tungstophosphoric acid-doped mesoporous silica
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An efficient, chemoselective and eco-friendly protocol for the protection of amines as N-tert-butylcarbamate using (Boc)2O and protection of alcohols as silyl ether using HMDS over tungstophosphoric acid/SBA15 has been developed. Solventless condition, easy work-up, short reaction time, excellent yields and reusability of the catalyst are the striking features of this methodology which can be considered to be one of the better methods for the protection of amines and alcohols.
- Karmakar, Bikash,Banerji, Julie
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experimental part
p. 3855 - 3858
(2010/08/20)
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- Magnesium hydrogensulfate [Mg(HSO4)2] as an efficient catalyst for the preparation of silyl ethers, dibenzo[a,j]xanthenes, and octahydroxanthene derivatives
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Magnesium hydrogensulfate [Mg(HSO4)2], as a heterogeneous solid acid catalyst, has been used for the mild formation of trimethylsilyl (TMS) ethers from various primary, secondary, and tertiary aliphatic alcohols; aromatic alcohols; a
- Shaterian, Hamid Reza,Doostmohammadi, Razieh,Khorami, Fahimeh,Ghashang, Majid
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experimental part
p. 171 - 180
(2010/04/05)
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- Rapid assembly of explicit, functional silicones
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The impressive surface activity of silicones can be enhanced by the incorporation of hydrophilic organic functional groups and polymers. Traditional routes to such compounds, which typically involve platinum-catalyzed hydrosilylation, suffer from incompatibility with certain functional groups. B(C6F5)3-catalyzed condensation of hydrosilanes with alkoxysilanes offers new opportunities to prepare explicit silicone structures. We demonstrate here that conversion of alcohols to silyl ethers competes unproductively with alkoxysilane conversion to disiloxanes. By contrast, a wide range of structurally complex alkyl halide and oligovinyl compounds can be readily made in high yield. Thermal 3+2-cycloadditions and thiol-ene click reactions are used to convert these compounds into surface active materials. The Royal Society of Chemistry.
- Grande, John B.,Gonzaga, Ferdinand,Brook, Michael A.
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scheme or table
p. 9369 - 9378
(2011/01/07)
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- Unsuccessful attempts to add alcohols to transient 2-amino-2-siloxy- silenes-leading to a new benign route for base-free alcohol protection
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Thermolytic formation of transient 1,1-bis(trimethylsilyl)-2-dimethylamino- 2-trimethylsiloxysilene (2) from N,N-dimethyl(tris(trimethylsilyl)silyl) methaneamide (1) in presence of a series of alcohols was investigated. The products are, however, not the expected alcohol-silene addition adducts but silylethers formed in nearly quantitative yields. Thermolysis of 1 in the presence of both alcohols (MeOH or iPrOH) and 1,3-dienes (1,3-butadiene or 2,3-dimethyl-1,3-butadiene) gives alkyl-tris(trimethylsilyl)silylethers and the [4+2] cycloadducts between the silene and diene, which confirms the presence of 2 and that it is unreactive towards alcohols. The observed silylethers are substitution adducts where the amide group of the silylamide is replaced by an alkoxy group, and the reaction time is reflected in the steric bulk of the alcohol. Indeed, the formation of silylethers from the reaction of alcohols with silylamide represents a new base-free method for protection of alcohols. The protection reactions using 1 progresses at elevated temperatures, or alternatively, under acid catalysis at ambient temperature, and similar protections can be carried out with N-cyclohexyl(triphenylsilyl)methaneamide and N,N-dimethyl(trimethylsilyl)methaneamide. The latter silylamide can be used under neutral conditions at room temperature. The only by-products are formamides (N,N-dimethylformamide (DMF) or N-cyclohexylformamide), and the reactions can be performed without solvent. In addition to alcohols we also examined the method for protection of diols, thiols and carboxylic acids, and also these reactions proceeded in high yields and with good selectivities. The Royal Society of Chemistry.
- Guliashvili, Tamaz,Tibbelin, Julius,Ryu, Jiyeon,Ottosson, Henrik
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supporting information; experimental part
p. 9379 - 9385
(2011/01/07)
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- A Facile and efficient trimethylsilylation of hydroxyl groups using silica-supported zinc chloride and alumina-supported sodium hydrogensulfate as recyclable heterogeneous catalysts
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Silica-supported zinc chloride (SiO2-ZnCl2) and novel alumina-supported sodium hydrogensulfate (NaHSO4-Al 2O3) as recyclable heterogeneous catalysts have been used for the mild trimethylsilylation of hydroxyl groups under ambient conditions. This procedure also allows for the selective protection of primary and secondary alcohols in the presence of tertiary alcohols.
- Shaterian, Hamid Reza,Khorami, Fahimeh,Doostmohammadi, Razieh,Amirzadeh, Azita,Ghashang, Majid
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experimental part
p. 2227 - 2237
(2010/04/25)
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- Efficient and practical protocol for silylation of hydroxyl groups using reusable lithium perchlorate dispread in silica gel under neutral condition
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A very efficient and mild procedure for the trimethylsilylation of a wide variety of alcohols, including primary, allylic, benzylic, secondary, hindered secondary, tertiary, and phenols with hexamethyldisilazane on the surface of silica gel dispersed with LiClO4 in room temperature at few minutes in excellent yields under neutral conditions is reported. This procedure also allows the excellent selectivity under LP-SiO2 system for silylation of alcohols in the presence of amine and phenolic hydroxy groups.
- Azizi, Najmedin,Yousefi, Rozbeh,Saidi, Mohammad R.
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p. 817 - 820
(2007/10/03)
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- Aluminium triflate [Al(OTf)3] as a recyclable catalyst for the conversion of α-hydroxyphosphonates, alcohols and phenols to their corresponding O-silylated products with hexamethyldisilazane (HMDS)
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Al(OTf)3 as a recyclable catalyst conducts the efficient conversion of various types of α-hydroxyphosphonates to their corresponding α-trimethysilyloxyphosphonates with HMDS in the absence of solvent at room temperature. The general applicabili
- Firouzabadi, Habib,Iranpoor, Nasser,Sobhani, Sara,Ghassamipour, Soheila
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p. 595 - 599
(2007/10/03)
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- Antistatic and antidust agents, compositions thereof, and methods of manufacture
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A quaternary onium aromatic sulfonate represented by the formula: wherein each R1 independently comprises substituted or unsubstituted, aliphatic or aromatic, hydrocarbyl, carbocyclic or heterocyclic radicals, each X is selected from the group
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Page/Page column 11
(2008/06/13)
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- A Convenient Method for Protection and Deprotection of Alcohols and Phenols as Alkylsilyl Ethers Catalyzed by Iodine under Microwave Irradiation
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Irradiation of alcohols or phenols with tert-butyldimethylsilyl chloride (TBDMSCl) or trimethylsilyl chloride (TMSCl) in presence of catalytic amount (20 mol%) of iodine in a microwave oven for 2 min gives the corresponding silyl ethers in excellent yield. Iodine in methanol deprotects the silyl ether into its parent alcohol or phenol under similar reaction conditions.
- Saxena, Ira,Deka, Nabajyoti,Sarma, Jadab C.,Tsuboi, Sadao
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p. 4185 - 4191
(2007/10/03)
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- Silicon-29 NMR spectra of trimethylsilylated alcohols
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29Si NMR spectra of trimethylsilyl (TMS) derivatives of 26 simple alcohols were measured under standardized conditions (i.e., in sufficiently diluted deuteriochloroform solutions). Due to association with the solvent the chemical shifts are in almost all cases larger than those reported earlier for different solutions. This observation is in agreement with the proposed mechanism of steric effects as being due to sterically controlled association with the solvent. The use of chloroform as a solvent enhances steric effects hut at the same time it can reduce small differences due to polar effects in closely related compounds. In the studied class of compounds the gross dependence of the chemical shift on polar effects is not substantially affected by the change of the solvent.
- Kvicalova, Magdalena,Cermak, Jan,Blechta, Vratislav,Schraml, Jan
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p. 816 - 820
(2007/10/03)
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- Adhesion additives and curable organosiloxane compositions containing same
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The novel organosiloxane compounds of the present invention are characterized by the presence of 1) a silicon atom containing at least two alkoxy or other hydrolyzable groups and the group -OR1Si≡ wherein R1represents a divalent orga
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- Donor-Acceptor Accelerated Norbornadiene Rearrangements
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The norbornadienone acetals 3 with a CO2Me, CONMe2 or CHO substituent at C-2 undergo rearrangement under very mild conditions; cycloheptatrienes are obtained for CO2Me and CONMe2 substituents and the furanone acetal 9 for the CHO substituent.The donor-acceptor acceleration is consistent with a formal 1,3-shift to a norcaradiene proceeding either via a zwitterionic intermediate or a concerted-forbidden path.Rearrangement via a biradical is not consistent with the slower rearrangement of 7-cyano-7-methoxy-2,3-bis(methoxycarbonyl)norbornadiene 16.The indene 19 racemises rapidly at a temperature 100 deg C below that required for 18 establishing that a donor and an acceptor (Me3SiO and CN) at a potential radical centre promote homolysis to a greater extent than two groups (two alkoxy groups).
- Bleasdale, Christine,Jones, David W.
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p. 2441 - 2452
(2007/10/02)
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- Carbohydrates as chiral auxiliaries: Synthesis of 2-hydroxy-β-D-glucopyranosides
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A new 2-step, 1-pot procedure for the stereoselective glycosylation of allylic alcohols with 1,2-di-O-benzoyl-β-D-glucopyranosides to produce 2-hydroxy-β-D-glucopyranosides has been developed. The required precursor for the glycosylation was readily obtained from tri-O-benzyl-D-glucal in 2 steps (91% overall).
- Charette,Marcoux,Cote
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p. 7215 - 7218
(2007/10/02)
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- Synthesis of Trimethylsilyloxy and Hydroxy Compounds from Carbanions and Bis(trimethylsilyl)peroxide.
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The reactions of bis(trimethylsilyl)peroxide with alkyl, vinyl, alkynyl, aromatic and heteroaromatic anions are described.Depending on the reaction conditions, the trimethylsilyloxy derivatives can be obtained alone or together with the corresponding trimethylsilyl derivatives, which is sometimes the major product.Enolates, generated using magnesium diisopropylamide give the corresponding hydroxycarbonyl compounds in good yields.An attempt to rationalise the above results is given, emphasising the wide use of bis(trimethylsilyl)peroxide in organic synthesis as an electrophilic hydroxylation reagent.
- Camici, Lucia,Dembech, Pasquale,Ricci, Alfredo,Seconi, Giancarlo,Taddei, Maurizio
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p. 4197 - 4206
(2007/10/02)
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- Synthesis of disiloxanes containing hydroxyalkyl groups
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Four 1,3-bis(ω-hydroxyalkyl)tetramethyldisiloxanes 2O (I; n = 3-6) were synthsized by methanolysis of the correspondig trimethylsilylterminated disiloxanes (III).The latter were obtained from 1,1,3,3-tetramethyldisiloxane (II) and the appropriate (ω-alkenyloxy)trimethylsilanes (IV).Under acidic conditions III formed in addition to I, the corresponding (ω-hydroxyalkyl)pentamethyldisiloxanes HO(CH2)nSiMe2OSiMe3 (V; n = 3-6).
- Braun, F.,Willner, L.,Hess, M.,Kosfeld, R.
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- SYNTHESIS OF DIOSPHENOL ETHERS BY MEANS OF ALKOXYTRIMETHYLSILANES
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α-Diketones may be O-alkylated with a variety of alkoxytrimethylsilanes.
- Ponaras, A. A.,Meah, Md. Younus
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p. 4953 - 4956
(2007/10/02)
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- Reagents and synthetic methods. 18 : N-trimethylsilyl-2-oxazolidinone, a useful silyating agent for hydroxy compounds
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N-trimethylsilyl-2-oxazolidinone reacts rapidly with alcohols at room temperature with the catalytic assistance of chlorotrimethylsilane to give high isolated yields of trimethylsilyl ethers.
- Aizpurua, Jesus Mari,Palomo, Claudio
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p. 265 - 268
(2007/10/02)
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