- NEW ANHYDROUS FLUORINATING SYSTEMS: THE COMBINATION OF CROWN-ETHERS AND CESIUM FLUORIDE. A RELATIVE RATE STUDY.
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New, anhydrous fluorinating systems are presented. 18-Crown-6 or dibenzo-24-crown-8 act as solid - liquid phase transfer catalysts with cesium fluoride.A catalytic amount of these crown ethers with CsF increased the rate of fluorodestannylation of trialkyltin mercaptides (used as a good fluoride probe) by a factor of 5-7.In addition, alkyl bromides, such as benzyl bromide, reacted in a similar way.Kinetic evidence for "sandwich" or "edge" complexes with the cesium cation and 18-crown-6 is presented.
- Gingras, Marc,Harpp, David N.
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- Fluoro-Substituted Methyllithium Chemistry: External Quenching Method Using Flow Microreactors
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The external quenching method based on flow microreactors allows the generation and use of short-lived fluoro-substituted methyllithium reagents, such as fluoromethyllithium, fluoroiodomethyllithium, and fluoroiodostannylmethyllithium. Highly chemoselective reactions have been developed, opening new opportunities in the synthesis of fluorinated molecules using fluorinated organometallics.
- Colella, Marco,Degennaro, Leonardo,Higuma, Ryosuke,Ishikawa, Susumu,Luisi, Renzo,Nagaki, Aiichiro,Takahashi, Yusuke,Tota, Arianna
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supporting information
p. 10924 - 10928
(2020/05/08)
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- Organic tin compound cycle application Stille method of synthesis of biphenyl
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The invention provides a method for synthesizing diphenyl through Stille reaction recycling with an organotin compound, and relates to a method for preparing diphenyl through a Stille reaction. A purpose of the present invention is to solve the problem of low organotin utilization rate of the existing Stille method for preparing the diphenyl compound. The method comprises: 1, adopting tri-butyltin chloride and bromobenzene as raw materials, and carrying out a reaction under the effect of a Grignard reagent to synthesize tributylphenyltin; 2, carrying out a reaction of a mixed solution of halogenated benzene, tributylphenyltin, cuprous iodide, lithium chloride, palladium(triphenylphosphine)dichloride and cesium fluoride DMF to prepare diphenyl, and collecting the filter residue; 3, dissolving the filter residue with acetone, dissolving the insoluble matter with absolute alcohol, and concentrating to obtain fluorotributyltin; and 4, converting the tin fluoride into the organic tin chloride with saturated ammonium chloride tetrahydrofuran. According to the present invention, the synthesis process conditions are optimized, the highest yield of the diphenyl compound achieves 97%, and the effective separation utilization of the organic tin chloride is achieved.
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Paragraph 0051; 0053-0054
(2017/05/12)
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- Palladium complex-catalyzed germylation of allylic halides using (germyl)stannanes
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(Triethylgermyl)tributylstannane reacts metal-selectively with allylic halides at room temperature (r.t.) in the presence of tris(dibenzylideneacetone)dipalladium, Pd2(dba)3CHCl3, to provide an alternative route to allylge
- Nakano, Taichi,Ono, Kazuyoshi,Senda, Yoshiya,Migita, Toshihiko
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p. 313 - 317
(2007/10/03)
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- Reactivity of carbon dioxide with n-butyl(phenoxy)-,(alkoxy)-, and (oxo)stannanes: insight into dimethyl carbonate synthesis
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The CO2 insertion into Sn-O bonds of a series of butyl(phenoxy)-, (alkoxy)-, and (oxo)-stannanes has been investigated. The tributyl derivatives Bu3SnOR (2a, R = Me; 3a, R = iPr; 4a, R = tBu; 5a, R = SnBu3)1 give quantitatively Bu3Sn(OCO2R), 2b-5b; the analogous tributylphenoxystannane, 1, is less reactive. For the dibutyl series, Bu2Sn(OR)2, steric effects of tBu groups in OR (8a) suppress carbonation under atmospheric pressure. With R = Me (6a) or R = iPr (7a), only one Sn-OR bond reacts, resulting in Bu2Sn(OR)(OCO2R), 6b or 7b. Treating 6a with 2-propanol affords under CO2 the mixed compound Bu2Sn(OMe)-(OCO2iPr), selectively. Facile deinsertion of CO2 is a common property of all compounds, occurring more readily in the dibutyl series. The stoichiometric transformation of the carbonato ligand in 2b, 5b, or 6b to dimethyl carbonate (DMC) on reaction with MeI requires nucleophilic assistance by F- to proceed. In the presence of MeOH, 2b and 5b are almost inactive for DMC formation, in contrast with 6b. The best yield is obtained under supercritical CO2-methanol conditions.
- Ballivet-Tkatchenko,Douteau,Stutzmann
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p. 4563 - 4567
(2008/10/08)
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- Antifungal sordaridin derivatives
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A compound of formula STR1 wherein Z is a tetrahydro-pyrano group selected from STR2 having antifungal activity processes for their preparation and their use in medicines.
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- Oxo fluorides of titanium and vanadium. Preparation and crystal structures of [Cp*TiF(μ-O)]4 and OVF2N=PPh3
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The reaction of Cp*TiF3 (Cp* = C5Me5) (1) with O(SnBu3)2 affords the eight-membered ring compound [Cp*TiF(μ-O)]4 (2) with elimination of Bu3SnF. This is the first example of an organometallic oxo fluoride of group 4 of the periodic table. The molecular structure of 2 has been determined by X-ray crystallography. It shows that the eight-membered ring is almost planar. The reaction of OVF3 with Ph3P=NSiMe3 yields OVF2N=PPh3 (3), which can be treated again with Ph3P=NSiMe3 to give OVF(N=PPh3)2 (4). The crystal structure of 3 shows that this compound is a monomer in the solid state. The oxo fluorides have characteristic differences in their structures or reactions compared to the corresponding chlorides.
- Roesky, Herbert W.,Leichtweis, Iring,Noltemeyer, Mathias
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p. 5102 - 5104
(2008/10/08)
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- QUELQUES ASPECTS DE LA REACTIVITE DE L'α-CHLORO α-ETHOXYMETHYLTRIBUTYLETAIN: ETHERIFICATION REDUCTRICE DES ALDEHYDES AROMATIQUES ET MISE EN EVIDENCE DE FORMYLTRIBUTYLETAIN LORS DE LA REACTION D'HYDROLYSE
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α-Chloro-α-ethoxymethyltributyltin reacts with aromatic aldehydes and leads to benzyl ethyl ethers with formation of tributyltin chloride and carbon monoxide.Analogously the formation of ethoxymethyltributyltin and tributyltyn chloride on hydrolysis of this new organometallic reagent is explained by a process involving formyltributyltin as an unstable intermediate.This explanation is supported by the observation of an electronic spectrum between 350 and 450 nm during the hydrolysis.
- Quintard, Jean-Paul,Elissondo, Bernard,Mouko-Mpegna, David
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p. 175 - 188
(2007/10/02)
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- Controlled release of compounds utilizing a plastic matrix
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A composition and method for the controlled release of compounds from a plastic dispenser, usually a thermoplastic, generally in association with a porosigen in contact with water, for example, an aquatic environment or soil moisture. Thermoplastic dispensers are generally made from a water insoluble polymer such as polyethylene, polypropylene, ethylene vinyl acetate, polyamide, polystyrene, polyvinyl acetate, polyurethane, etc. Thermoset plastics, such as epoxy, are also used. The porosigen, depending upon the desired end use and release rate of a compound, can have a solubility of less than 0.1 or 0.001 grams per 100 grams of water, or up to 100 grams per 100 grams of water. The released compound, for example, a larvicide, a molluscicide, a nematicide, a trace nutrient, a plant regulant, etc., is contained in the thermoplastic dispenser. The combination of the plastic dispenser containing the porosigen and compound results in a slow release which can last for days, months, and even years, through dissolution of the porosigen and the formation of a porous network permitting water to contact the dispersed compound located in the interior portions of the dispenser.
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- Synthesis of (+/-)-Lavandulol and its Related Homoallylic Alcohol via Allyl Transfer from Sulphur to Tin
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(+/-)-Lavandulol and related homoallylic alcohols were prepared by the stannolysis of allylic sulphones and the subsequent hydroxymethylation of the resulting allylic stannanes with trioxan-BF3*OEt2.
- Ueno, Yoshio,Aoki, Seiichi,Okawara, Makoto
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p. 683 - 684
(2007/10/02)
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