- Synthesis method of 1, 2-bis (alkyl-siloxy) ethane
-
The invention provides a synthesis method of 1, 2-bis (alkyl-siloxy) ethane, and belongs to the technical field of battery electrolytic solution additives. The method comprises the following steps: adding dichloromethane and ethylene glycol into a reaction kettle, cooling to 15 DEG C or below, adding imidazole, continuously cooling to -15 DEG C or below, starting to dropwise add vinyl dimethyl chlorosilane or tert-butyl dimethyl chlorosilane or trimethylchlorosilane, controlling the temperature in the dropwise adding process to range from -15 DEG C to -25 DEG C, after dropwise adding is completed for 1.8-2.2 h, washing the system with water, carrying out liquid separation, drying, carrying out suction filtration, collecting dichloromethane under reduced pressure, and rectifying to obtain 1, 2-bis (dimethyl vinyl siloxy) ethane or 1, 2-bis (tert-butyl dimethyl siloxy) ethane or 1, 2-bis (trimethyl siloxy) ethane. The synthesis method is simple, and the yield of the synthesized product is high.
- -
-
Paragraph 0031-0033
(2021/06/06)
-
- Pinacolatoboron fluoride (pinBF) is an efficient fluoride transfer agent for diastereoselective synthesis of benzylic fluorides
-
The incorporation of alkoxy ligands within a range of alkoxyfluoroboranes and dialkoxyfluoroboranes results in fluoroborane reagents with attenuated Lewis acidity and increased ability to donate fluoride ion(s) when compared to boron trifluoride itself. Pinacolatoboron fluoride (pinBF), prepared in situ from BF3·OEt2 and bis(O-trimethylsilyl)pinacol, has been identified as an efficient fluoride donor which allows highly stereoselective SN1-type epoxide ring-opening (with retention of configuration) of a range of trans-β-methyl-substituted aryl epoxides to give the corresponding syn-fluorohydrins. The substrate scope of this transformation is more broad than the analogous protocol using boron trifluoride alone.
- Cresswell, Alexander J.,Davies, Stephen G.,Figuccia, Aude L.A.,Fletcher, Ai M.,Heijnen, Dorus,Lee, James A.,Morris, Melloney J.,Kennett, Alice M.R.,Roberts, Paul M.,Thomson, James E.
-
supporting information
p. 3373 - 3377
(2015/06/02)
-
- Total synthesis of (-)-hippodamine by stereocontrolled construction of azaphenalene skeleton based on extended one-pot asymmetric azaelectrocyclization
-
The first asymmetric total synthesis of (-)-hippodamine has been accomplished via the concise construction of its azaphenalene core, which is featured by the 2,4,6-chiral piperidine synthesis based on one-pot asymmetric azaelectrocyclization in the partially activated substituent system and the subsequent intramolecular Mannich reaction.
- Fujita, Shintaro,Sakaguchi, Taku,Kobayashi, Toyoharu,Tsuchikawa, Hiroshi,Katsumura, Shigeo
-
supporting information
p. 2758 - 2761
(2013/07/19)
-
- The pentamethylcyclopentadienylsilicon(II) cation as a catalyst for the specific degradation of oligo(ethyleneglycol) diethers
-
Catalytic open sandwiches: Oligo(ethyleneglycol) diethers RO(CH 2CH2O)nR are degraded by the unusual catalyst Cp Si+ (see scheme). The open coordination sphere at silicon allows up to four Si-O contacts; crystal structure data of the reactive compounds [Cp Si(dme)]+BR4- and [Cp Si([12]crown-4)] +BR4- (R=C6F5) show weakly bound ether molecules. Copyright
- Leszczynska, Kinga,Mix, Andreas,Berger, Raphael J. F.,Rummel, Britta,Neumann, Beate,Stammler, Hans-Georg,Jutzi, Peter
-
supporting information; experimental part
p. 6843 - 6846
(2011/09/19)
-
- METHOD OF MANUFACTURING (3R, 4S) -1- (4-FLUOROPHENYL) -3- [ (3S) -3- (4 -FLUOROPHENYL) -3-HYDROXYPROPYL) ] -4- (4-HYD ROXYPHENYL) -2-AZETIDINONE
-
A method of manufacturing (3R,4S)-l-(4-fluorophenyl)-3-[(3S)-3-(4-fluorophenyl)-3- hydroxypropyl)]-4-(4-hydroxyphenyl)-2-azetidinone (Ezetimibe) of formula I, starting from the optically active (S)-N-acyl-oxazolidide of formula II, which is reacted with an alkyleneglycol of general formula III, (stage 1), and the obtained acetal-oxazolidide of general formula IV, is subjected to reaction with a silyl-imine of general formula V the produced amino-oxazolidide of general formula VI, (stage 3), and the obtained silylated azetidinone of general formula VII, is desilylated (stage 4), and the ketal of general formula VIII produced this way, is deketalized formula IX is finally reduced.
- -
-
Page/Page column 9-10
(2008/12/07)
-
- Ester dienolate [2,3]-Wittig rearrangement in natural product synthesis: Diastereoselective total synthesis of the triester of viridiofungin A, A 2, and A4
-
An ester dienolate [2,3]-Wittig rearrangement was utilized to access the alkylated citric acid skeleton 6 that is characteristic for the viridiofungins and other members of the alkyl citrate family of secondary natural products. The [2,3]-sigmatropic rearrangement of (Z,Z)-15 provided the rearrangement product (±)-syn-16 in moderate yield and with very good diastereoselectivity. A Julia-Kocienski olefination efficiently served to connect the polar head (±)-syn-26 with the lipophilic tail (32a-c) of the viridiofungins. Amide formation between the racemic viridiofungin precursors 35a-c and the enantiomerically pure amino acid L-tyrosine methyl ester followed by preparative reversed-phase HPLC provided the isopropyl dimethyl ester of viridiofungin A ((+)-39a), A2 ((+)-39b), and A4 ((+)-39c) as well as the nonnatural diastereomers (-)-38a-c.
- Pollex, Annett,Millet, Agnes,Mueller, Jana,Hiersemann, Martin,Abraham, Lars
-
p. 5579 - 5591
(2007/10/03)
-
- Ring-opening reactions of cyclic acetals and 1,3-oxazolidines with halosilane equivalents
-
Reactions of acetal and 1,3-oxazolidine rings were examined using two kinds of iodosilane equivalent reagents, a 1:2 mixture of Me3SiNEt2 and MeI (reagent 1a) and a 1:1 mixture of Et3SiH and MeI containing a catalytic amount of PdCl2 (reagent 1b). In the reactions of alkanone ethylene acetals with reagent 1a, a C-O bond in the acetal ring readily cleaved to give 2-(trimethylsiloxy)ethyl enol ethers. Similarly, the C-O bond of 1,3-oxazolidine rings cleaved to give ring-opened imine or enamine derivatives. The reactions of aromatic ketone ethylene acetals and cyclohexanone trimethylene acetal led to deprotection of the acetal unit to liberate free ketones. With reagent 1b, cycloalkanone ethylene acetal afforded a dimeric product with 2-iodoethyl alkenoate moieties, while aromatic ketone ethylene or trimethylene acetals produced deprotected ketones.
- Iwata, Arihiro,Tang, Heqing,Kunai, Atsutaka,Ohshita, Joji,Yamamoto, Yasushi,Matui, Chinami
-
p. 5170 - 5175
(2007/10/03)
-
- A Convenient Procedure for the Synthesis of Acetals from α-Halo Ketones
-
A study for determining the scope and limitations of a procedure for synthesising ethylene acetals from haloketones is presented. The method uses 1,2-bis(trimethylsilyloxy)ethane, BTSE, as reagent and Nafion-TMS as catalyst. Two procedures have been tested: (A) stoichiometric amounts of the haloketone and BTSE and a catalytic amount of Nafion-TMS were heated to reflux in chloro-form solution, and (B) stoichiometric amounts of the reactants and a catalytic amount of Nafion-TMS were heated to 90-100°C in the absence of solvent. The following ketones have been tested: 2-bromo-1-phenyl-1-ethanone, 2-bromo-cyclopentenone, 3-bromo-3-methyl-2-butanone, 3-chloro-3-methyl-2-butanone, 1-bromo-3,3-dimethyl-2-butanone, 1-chloro-3,3-dimethyl-2-butanone, 2-bromocyclohexanone, 2-chloro-1-cyclohexyl-1-ethanone, 1,1-dibromo-3,3-dimethyl-2-butanone, 1,3-dibromo-3-methyl-2-butanone, 1,3-dibromo-2-butanone, 1,3-dibromo-2-propanone, 2-chloro-1-phenyl-1-ethanone, and endo-2-bromocamphor. Yields were in the range 57-100% with the exceptions of endo-2-bromocamphor which afforded 10% yield and the dibromoketones 1,1-dibromo-3,3-dimethyl-2-butanone and 1,3-dibromo-3-methyl-2-butanone for which the method failed. Factors determining the scope and limitations are briefly discussed. Full experimental details and spectroscopic data of the acetals are given.
- Carlson, Rolf,Gautun, Hanna,Westerlund, Andreas
-
-
- Towards the diastereoselective functionalization of non-racemic acetal derivatives of η6-arylcarbonyl complexes of tricarbonylchromium
-
(S)-Butane-1,2,4-triol (2) has been investigated as a potential chiral auxiliary for the formation of non-racemic acetals derived from η6-arylcarbonyl complexes of tricarbonylchromium. Predominantly the cis dioxan (5) was formed from benzaldehyde, leading to preparation of the η6-Cr(CO)3 complex (16), and of the derived complexes (23) and (24). Lithiation-electrophile quenching of these complexes gave a mixture of products arising from ortho and benzylic functionalization. Reaction of acetophenone, or of the η6-Cr(CO)3 complexes (45) or (46), with either the triol (2) or its tris(silyl) ether (15) under conditions of kinetic or thermodynamic control gave an inseparable mixture of acetals.
- Kendall, Jackie D.,Woodgate, Paul D.
-
p. 1083 - 1096
(2007/10/03)
-
- Silicon-29 NMR spectra of tert-butyldimethylsilyl and trimethylsilyl derivatives of some non-rigid diols
-
29Si NMR spectra of trimethylsilyl (TMS) and tert-butyldimethylsilyl (TBDMS) derivatives of selected diols were measured under standardized conditions (i.e., in diluted CDCl3 solutions). Application of the recently reported correlation between the chemical shifts in TMS and TBDMS derivatives revealed considerable and systematic deviations which exceeded experimental errors and error estimates from the correlation. Two possible explanations of the deviations are considered: interaction between the two bulky substituent groups and invalidity of the reported correlation for simple hydroxy derivatives. An independent study of analogous derivatives of monohydroxy compounds has shown that the linear correlation holds but the slope and intercept are significantly different from those reported previously on the basis of a study of amino acid derivatives. The data obtained for the diol derivatives fit the new correlation very well and no indication of an interaction between the bulky TBDMS groups was noticed. However, deviations do occur in branched diol derivatives in which branching reduces accessibility of the oxygen atoms surface to associate with proton donors. The largest deviation was found when intramolecular hydrogen bond was formed.
- Kvicalova, Magdalena,Blechta, Vratislav,Kobylczyk, Krzysztof,Piekos, Ryszard,Schraml, Jan
-
p. 761 - 768
(2007/10/03)
-
- Reaction of hexafluorobenzene with trimethylsilyl ethers
-
Hexafluorobenzene reacts readily with a variety of trimethylsilyl ethers ROSiMe3 (R = CF3CH2, FCH2CH2, H(CF2)nCH2 (n = 2, 4), CF3(CF2)6CH2, CF3(CF2)5CH2CH2, Me3SiOCH2CH2, C6F5OCH2CH2, C6H5, 4-FC6H4) to give from mono- to hexapolyfluoroalkoxy- and polyfluoroaryloxy-benzenes.The structure of C6(OCH2CF3)6 has been confirmed by single-crystal X-ray analysis.The perfluorinated ether C6F5OCF2CF3 may be synthesized from C6F5OCH2CF3 by chlorination and subsequent fluorination with SbF3/SbCl5.The chlorination of 5,6,7,8-tetrafluoro-1,4-benzodioxane is also discussed.
- Zhang, Y. F.,Kirchmeier, Robert L.,Shreeve, Jean'ne M.
-
p. 287 - 292
(2007/10/02)
-
- SOME KINETIC RELATIONSHIPS OF THE REACTION OF 2-ETHOXY-1,3-DIOXOLANE WITH HEXAMETHYLDISILOXANE
-
The exchange reaction of hexamethyldisiloxane with 2-ethoxy-1,3-dioxolane in the presence of p-toluenesulfonic acid as catalyst is of first order in the components and of second order in the catalyst.The activation energy is 38 +/- 1 kJ/mol.The process rate is determined by the stage involving reaction of the protonated form of 2-ethoxy-1,3-dioxolane with hexamethyldisiloxane.
- Nedogrei, E. P.,Zhurkina, I. P.,Musavirov, R. S.,Syrkin, A. M.,Rakhmankulov, D. L.
-
p. 934 - 936
(2007/10/02)
-
- Reactions of trimethyliodosilane with mono-, di-, and trioxacycloalkanes
-
The reactions of Me3SiI with mono-, di-, and trioxacycloalkanes have been studied first.Preparative methods for the synthesis of some promising synthones, namely α,ω-diiodoalkanes, α,ω-alkanediols, and iodomethyl ω-iodoalkyl ethers, have been developed based on these reactions.The effect of the cycle size and the nature of the substituent on the course of the reactions is demonstrated.Schemes for the mechanism of the reactions are suggested.
- Voronkov, M. G.,Dubinskaya, E. I.
-
-
- Counterattack Reagent Bis(trimethylsilyl)acetamide in the Disilylation of Diols
-
The counterattack method was applied to the disilylation of diols.Treatment of various diols with 0.3 or 1.1 equivalents of potassium hydride and 1.1 equivalents of bis(trimethylsilyl)acetamide in THF gave the corresponding disilyl ethers in good to excellent yields (60-95percent).The diols may contain other functionalities, such as amide, amine, ether, and thioether.The diols used in the disilylation were 2a-14a.The newly developed disilylation proceeded in one flask by a sequential deprotonation-silylation-deprotonation-silylation pathway.This disilylation also represents an example of a "tandem double-counterattack process".Bis(trimethylsilyl)acetamide acted as a counterattack reagent; it provided two Me3Si groups to diols and produced amides as bases.
- Hwu, Jih Ru,Anderson, Denise A.,Wang, Naelong,Buchner, Meredith M.,Gani, Paul,Tsay, Shwu-Chen
-
p. 1667 - 1671
(2007/10/02)
-
- Mechanistic Studies of Diastereoselective Cyclopropanation via Homochiral Ketals. 2. Studies with Conformationally Restricted 2-Cyclohexen-1-one Ketals
-
The effect of cyclohexene ring conformation on the diastereoselectivity observed for Simmons-Smith cyclopropanation of 2-cyclohexen-1-one ethylene ketals was examined by using (5S)-5-tert-butyl-2-cyclohexen-1-one 1,2-ethanediol, (2R,3R)-2,3-butanediol, and (2S,3S)-2,3-butanediol ketals.Reagent chelation by the pseudoequatorial dioxolane oxygen atom was shown to result in more effective methylene transfer.This regiochemical preference can either antagonize or reinforce diastereoselectivity due to steric hindrance of the dioxolane oxygen atoms from dissymmetric placement of methyl appendages on the dioxolane ring.
- Mash, Eugene A.,Hemperly, Susan B.
-
p. 2055 - 2060
(2007/10/02)
-
- REACTION OF HEXAMETHYLDISILOXANE WITH 2-ETHOXY-1,3-DIOXOLANE
-
The reaction of hexamethyldisiloxane with 2-ethoxy-1,3-dioxolane is described.It is shown that cleavage of the endo- and exocyclic carbon-oxygen bonds of the ortho ester occurs under mild condition (16 - 20 deg C) in the presence of acidic catalysts with
- Zhurkina, I. P.,Nedogrei, E. P.,Musavirov, R. S.,Kondrat'eva, I. A.,Rakhmankulov, D. L.
-
p. 1338 - 1342
(2007/10/02)
-
- Capillary gas-chromatographic analysis of monosaccharides: Improvements and comparisons using trifluoroacetylation and trimethylsilylation of sugar O-benzyl- and O-methyl-oximes
-
Two new procedures for the gas-chromatographic analysis of monosaccharides are reported. One involves derivatization of the sugars by reaction with O-benzylhydroxylamine followed by trifluoroacetylation with N-methylbis(trifluoroacetamide) and chromatography on a DB-1701 capillary column. This technique probably provides the best resolution achieved to date of the C3-C6 aldoses, as well as of the corresponding alditols. Ketoses can be qualitatively analyzed by this method, but complications interfere with their quantitative analysis. The second procedure also involves initial derivatization as the O-benzyloxime, but is followed by trimethylsilylation with 1-trimethylsilylimidazole, and chromatography on a DB-17 column. This technique is particularly useful for C5 sugars, C6 ketoses, and mixtures of sugars, alditols, and/or lactones. A number of additional, critical, observations on the derivatization and capillary gas-chromatographic analysis of monosaccharides are described.
- Andrews, Mark A.
-
-
- Organotin-mediated Synthesis of Macrocyclic Polyesters: Mechanism and Selectivity in the Reaction of Dioxastannolanes with Diacyl Dichlorides
-
The reaction of 2,2-di-n-butyl-1,3,2-dioxastannolane with diacyl dichlorides for the synthesis of macrocyclic tetraesters has been investigated to gain an insight into its mechanistic pathway and to ascertain the occurrence of genuine template effects.Experimental results show unambiguously that the reaction is a clean cyclo-oligomerization involving a fast transesterification equilibrium that affords a thermodynamic distribution of oligomeric esters.No evidence to support a structural or 'covalent' template effect by tin was found.Instead, dioxastannolane is not only the reagent, but also behaves as an efficient transesterification catalyst that equilibrates the macrocyclic ester mixture.In this context, the reaction can hardly be considered selective.
- Roelens, Stefano
-
p. 1617 - 1626
(2007/10/02)
-
- Group 4 Organometallic Reagents Part 6. The Organotin-mediated Monofunctionalization of Diols: an Insight into the Selective Monoesterification with Acyl Chlorides
-
The monoesterification of ethylene glycol with acyl chlorides through its dibutylstannylene derivative (1) has been selected as a model reaction to investigate, by n.m.r. spectroscopy, the the origin of the organotin-mediated selective monofunctionalization of diols.The reaction has been found to take place in two separates steps, namely, an initial fast formation of a stannylated diol monoester followed by a slower intermolecular transesterification.The latter affords diester products and regenerates the starting dioxastannolane (1).Thus, the success of monoesterification depends on the timing of quenching the intermediate and is ensured by the large rate difference between the two steps.The above transesterification is an equilibrium reaction, shifted towards (1), that eventually leads to complete formation of diesters.Dynamic phenomena exhibited by n.m.r. spectra reveal that such a transesterification equilibrium also takes place intramolecularly at a much faster rate, showing intramolecularity factors of the order of 1E7 with respect to its intermolecular counterpart.Dibutyltin dichloride (3), which forms in the reaction, exerts a catalytic effect enhancing the reactivity of dioxastannolane toward the ester functionality.Such a catalytic effect may be accounted for by the very fast and strongly biased equilibrium reaction that occurs between (1) and (3), leading to ring-opening of the highly stable dioxastannolane.The generality of the stannylation method is further confirmed by monosilylation, carried out with silyl chlorides.
- Roelens, Stefano
-
p. 2105 - 2110
(2007/10/02)
-
- TRIMETHYLSILYLATED N-ALKYL-SUBSTITUTED CARBAMATES. I. PREPARATION AND SOME REACTIONS
-
Trimethylsilyl N-monoalkyl- and N,N-dialkyl-carbamates have been made in 85-95percent yields by silylation of the corresponding ammonium carbamates with trimethylchlorosilane.Trimethylsilyl N,N-dimethylcarbamate can be used for silylation of alcohols, phenols, and carboxylic acids.The silylcarbamates react with carboxylic acid halides to give the corresponding acid amides.The reaction of trimethylsilyl carbamates with carboxylic anhydrides give the corresponding silyl carboxylate and acid amide, while the reaction with dicarboxylic anhydrides give the trimethylsilyl monoamide of the corresponding dicarboxylic acid, i.e.Me3SiO2CCONR1R2.
- Knausz, Dezsoe,Meszticzky, Aranka,Szakacs, Laszlo,Csakvari, Bela,Ujszaszy, Kalman
-
-
- A FACILE SYNTHESIS OF 2,3,4,6-TETRA-O-BENZYL-D-GLUCOPYRANOSYLIDENE ACETALS USING TRIMETHYLSILYL TRIFLUOROMETHANESULFONATE CATALYST
-
The application of acetalization of aldehydes and ketones by alkoxysilanes in the presence of trimethylsilyl trifluoromethanesulfonate catalyst to lactones and di-O-trimethylsilyl-α-diols gave readily the corresponding spiro ortho esters.
- Yoshimura, Juji,Horito, Shigeomi,Hashimoto, Hironobu
-
p. 375 - 376
(2007/10/02)
-