5582-62-7Relevant academic research and scientific papers
The 13C Hyperfine Splittings in ESR Spectra of Prop-2-ynyl and 1-(Trimethylsiloxy)prop-2-ynyl Radicals
Walton, J. C.
, p. 241 - 246 (1983)
The 13C satellite lines were observed in the 9.4 GHz ESR spectra of prop-2-ynyl and 1-trimethylsiloxyprop-2-ynyl radicals generated from precursors containing 13C in natural abundance.The 13C hfs indicate that prop-2-ynyl radicals adopt the ?-delocalized structure, not the ?-allenyl form.The hfs of 1-trimethylsiloxyprop-2-ynyl radicals indicate that there is appreciable delocalization of spin onto the trimethylsiloxy group and that the radical is essentially planar at C(1).A linear correlation of a(C) with a(H) is shown to hold for a number of neutral hydocarbon ?-delocalized radicals.The experimental hfs are compared with spin densities calculated by a variety of semiempirical and ab initio SCF MO methods.
Chlorozincate(II) acidic ionic liquid: Efficient and biodegradable silylation catalyst
Abbasi, Faezeh,Azizi, Najmedin,Abdoli-Senejani, Masumeh
, (2017/09/30)
A practical and highly efficient silylation of alcohol and phenol derivatives with hexamethyldisilazane (HMDS) using acidic ionic liquids under mild reaction conditions is described. A series of Br?nsted as well as Br?nsted–Lewis acidic ionic liquids were prepared and their performance investigated for the silylation of a wide variety of alcohols and phenols with HMDS. Imidazole- as well as N-methyl-2-pyrrolidone-based acidic ionic liquids have a higher catalytic activity for the protection of sensitive, hindered alcohols and phenols, thus providing an environmentally begin and versatile alternative to current acid catalysts. In addition, the acidic ionic liquids are reusable, being recovered easily and reused several times without significant deterioration in catalytic activity.
The influence of the organolithium reagent nature on the possibility of the O→Csp migration of the R3Si group in propynes HC≡CCH2OSiR3
Novokshonov,Medvedeva,Mareev
, p. 2264 - 2268 (2018/03/25)
A possibility of the O→Csp 1,4-migration of the R3Si group in silyl ethers of terminal acetylenic alcohols upon treatment with organolithium reagents (RLi) was studied. In the case of 3-trimethylsilyloxypropyne, depending on the nature of RLi, the heterolysis of the Si—O bond occurs either by the action of acetylide formed as a result of deprotonation with the formation of 3-trimethylsilylprop-2-yn-1-ol trimethylsilyl ether, or by the action of the metalation agent with the formation of propargyl alcohol. The realization of the O→Csp 1,4-migration of the Me3Si group requires the use of mild organolithium reagents (lithium hexamethyldisilazanide and diisopropylamide). Silyl ethers having steric hindrance at the carbon atom bonded to the reaction center or around the silicon atom do not react with the studied organolithium reagents.
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
Abri, Abdolreza,Ranjdar, Somayeh
, p. 929 - 934 (2014/10/16)
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.
A mild and highly efficient method for the preparation of silyl ethers using Fe(HSO4)3/Et3N by chlorosilanes
Abri, Abdolreza,Assadi, Mohammad Galeh,Pourreza, Samira
, p. 1449 - 1454 (2013/03/13)
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.
An expeditious, efficient green methodology for the Boc protection of amines and silyl protection of alcohols over tungstophosphoric acid-doped mesoporous silica
Karmakar, Bikash,Banerji, Julie
experimental part, p. 3855 - 3858 (2010/08/20)
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.
A concise, protection-free and divergent approach for the enantioselective syntheses of two pheromonal epoxide components of the fall webworm moth and other species
Du, Yu,Zheng, Jian-Feng,Wang, Zhi-Gang,Jiang, Li-Jiao,Ruan, Yuan-Ping,Huang, Pei-Qiang
supporting information; experimental part, p. 4619 - 4622 (2010/10/03)
(Figure presented) On the basis of Zhous modified Sharpless asymmetric epoxidation, sequential coupling reactions, and a divergent strategy, the protection-free syntheses of two main pheromonal components 1 and 5, found in the fall webworm moth, Hyphantria cunea, and other species have been accomplished in 10 steps (for two compounds). The overall yields are 31% for 1, 28% for 5, and 25% for both 1 and 5, respectively. The ee values of the final products 1 and 5 are at least 99%.
Novel and highly effective method for the trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS), catalyzed by I2 generated in situ using Fe(NO3)3 · 9 H 2O/NaI under heterogeneous and neutral conditions
Khazaei, Ardeshir,Rahmati, Sadegh,Rostami, Amin
experimental part, p. 1434 - 1438 (2009/10/16)
Structurally diverse alcohols and phenols were trimethylsilylated in a clean and efficient reaction with hexamethyldisilazane (HMDS) based on the use of I2 generated in situ from Fe(NO3)3 · 9 H2O/NaI. The reaction occurs very rapid in good-to-high yield in CH2Cl2 at room temperature, and the use of toxic and corrosive molecular I2 is avoided.
SN2′ boron-mediated Mitsunobu reactions - A new one-pot three-component synthesis of substituted enamides and enol benzoates
Berree, Fabienne,Gernigon, Nicolas,Hercouet, Alain,Chia, Hui Lin,Carboni, Bertrand
supporting information; experimental part, p. 329 - 333 (2009/07/04)
The conversion of (3-hydroxy-1-propen-1-yl)boronates to substituted enamides and enol benzoates is readily achieved in a one-pot procedure consisting of a regiocontrolled Mitsunobu reaction with convenient nucleophiles, followed by allylboration of aldehydes. Wiley-VCH Verlag GmbH & Co. KGaA, 2009.
A convenient catalyst for aqueous and protein Suzuki-Miyaura cross-coupling
Chalker, Justin M.,Wood, Charlotte S. C.,Davis, Benjamin G.
supporting information; experimental part, p. 16346 - 16347 (2010/01/29)
(Figure Presented) A phosphine-free palladium catalyst for aqueous Suzuki-Miyaura cross-coupling is presented. The catalyst is active enough to mediate hindered, ortho-substituted biaryl couplings but mild enough for use on peptides and proteins. The Suzuki-Miyaura couplings on protein substrates are the first to proceed in useful conversions. Notably, hydrophobic aryl and vinyl groups can be transferred to the protein surface without the aid of organic solvent since the aryl- and vinylboronic acids used in the coupling are water-soluble as borate salts. The convenience and activity of this catalyst prompts use in both general synthesis and bioconjugation.
