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1.
Reaction of 2 with bis(tributyltin) in the presence of 3 mol % Pd2(dba)3, 6 mol % XPhos, and 30 equiv of LiBr in wet and air bubbled THF at reflux for 8 h afforded the desired products 3 in 73–74% yields. The cross-coupling reaction of 3a with aryl iodides in the presence of 10 mol % Pd(PPh3)4 and 10 mol % CuI afforded the coupled products 4a–p in 47–90% yields. The coupling reaction of 3b with various alkynyl bromides having aryl-, alkyl, or trialkylsilyl group also afforded the corresponding 1,3-enynes 5a–g in 61–77% yields. 相似文献
2.
A series of 2,2-difluoro-2H-chromenes were synthesized from the tandem reactions of ethyl 3-bromo-3,3-difluoropropionate with salicylaldehyde derivatives in good yields under basic conditions. In acidic environment defluorination took place during the reaction. A plausible mechanism was proposed based on the experimental results. 相似文献
3.
The 2,2-difluorobenzodioxole moiety has been introduced in medicinal chemistry research as a potential metabolically more stable derivative of the benzodioxole fragment. Herein we present, to the best of our knowledge, the first synthesis of 4-chloro-2,2-difluoro[1,3]dioxole[4,5-c]pyridine, a 5-aza-derivative of the 2,2-difluorobenzodioxole, from simple and cheap starting materials. The chlorine atom in position 4 could be useful for further functionalisation by cross coupling reactions. 相似文献
4.
The reactions of oxalyl fluoride with electrophiles in the presence of alkali metal fluoride were carried out. In the reaction with CF3CH2OTf (Tf=CF3SO2) or CH3CH2OTf, the synthesis of di-ether (ROCF2CF2OR) and mono-ether (ROCF2COF) was achieved. The difference of the reactivities between these two compounds was discussed from the result of DFT calculations. 相似文献
5.
Difluoromethylation of 2-hydroxychalcones using sodium 2-chloro-2,2-difluoroacetate as the difluoro-methylating agent was developed. Under facile conditions, a wide range of aryl difluoromethyl ethers were obtained in yields of 36%-80%. It is noteworthy that the new addition products, 2,2-difluoro-2H-benzofuran derivatives, were also synthesized in the reactions. The yield of 2,2-difluoro-2H-benzofuran derivative could be up to 35% when 3-methyl-2-hydroxychalcone was used as the reactant. A plausible reaction mechanism was proposed. 相似文献
6.
W. James Feast Miquel Gimeno Alan M. Kenwright 《Journal of fluorine chemistry》2006,127(12):1533-1539
The syntheses and characterisations of 1,1-difluoro-2-heptyl-2-vinylcyclopropane and some of its isomers are described together with attempts to effect free radical ring opening polymerisation. We have recently shown that the parent monomer, 1,1-difluoro-2-vinylcyclopropane, undergoes predominantly 1,4-addition ring opening in contrast to the more usual 1,5-ring opening of other substituted vinylcyclopropanes and we find that the same anomalous behaviour occurs in this work confirming the influence of fluorine on the course of cyclopropane ring opening proposed by Dolbier. The presence of an alkyl chain modifies the ratios of 1,4- to 1,5-ring opening compared to that found in the unsubstituted parent monomer. In addition an the unexpected behaviour of different alkyl substituted buta-1,3-dienes towards difluorocarbene addition is described. 相似文献
7.
Albert Lévai 《Monatshefte für Chemie / Chemical Monthly》1992,123(5):461-464
Summary 2,2-Dimethylchromans19–36 have been synthesized by the hydrogenation of 2,2-dimethyl-2H-chromenes1–18 in acetic acid solution in the presence of 10% Pd-C catalyst.Dedicated to Prof. Dr. W. Fleischhacker on the occasion of his 60th birthday 相似文献
8.
Clarence Rodrigues Roger G. Hall Mark Montgomery Xiuhua Yang Yong Xiang Long Lu 《合成通讯》2019,49(16):1997-2004
A simple, and efficient synthesis of 2,2-difluoro-3H-benzothiophen-3-ol using readily available sodium chlorodifluoroacetate (SCDA) is reported. We also explore new chemistry of these difluoro compounds. The salient feature of this approach includes operational simplicity and offers potential access to synthetically challenging building blocks for further elaboration. Functional group transformations of this new heterocycle are also presented. 相似文献
9.
G. K. Kostov L. Sauguet B. Ameduri H. Kaspar T. Zipplies K. Hintzer 《Journal of polymer science. Part A, Polymer chemistry》2010,48(18):3964-3976
The radical copolymerization of vinylidene fluoride (VDF) and 1‐bromo‐2,2‐difluoroethylene (BDFE) in 1,1,1,3,3‐pentafluorobutane solution at different monomer molar ratios (ranging from 96/4 to 25/75 mol %) and initiated by tert‐butylperoxypivalate (TBPPI, mainly) is presented. Poly(VDF‐co‐BDFE) copolymers of various aspects (from white powders to yellow viscous liquids) were produced depending on the copolymer compositions. The microstructures of the obtained copolymers were characterized by 19F and 1H NMR spectroscopy and by elementary analysis and these techniques enabled one to assess the contents of both comonomers in the produced copolymers. VDF was shown to be more incorporated in the copolymer than BDFE. From the extended Kelen and Tudos method, the kinetics of the radical copolymerization led to the determination of the reactivity ratios, ri, of both comonomers (rVDF = 1.20 ± 0.50 and rBDFE = 0.40 ± 0.15 at 75 °C) showing that VDF is more reactive than BDFE. Alfrey‐Price's Q and e values of BDFE monomer were calculated to be 0.009 (from QVDF = 0.008) or 0.019 (from QVDF = 0.015) and +1.22 (vs. eVDF = 0.40) or +1.37 (vs. eVDF = 0.50), respectively, indicating that BDFE is an electron‐accepting monomer. Statistic cooligomers were produced with molar masses ranging from 1,800 to 5,500 g/mol (assessed by GPC with polystyrene standards). A further evidence of the successful copolymerization was shown by the selective reduction of bromine atoms in poly(VDF‐co‐BDFE) cooligomers that led to analog PVDF. The thermal properties of the poly(VDF‐co‐BDFE) cooligomers were also determined and those containing a high VDF amount exhibited a high thermal stability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3964–3976, 2010. 相似文献
10.
Yu Yang 《Journal of fluorine chemistry》2004,125(12):1825-1828
A stable carbocation was prepared by reacting bis(2-chloro-2,2-difluoroethyl) difluoroformal with SbF5. The carbocation's structure was confirmed by 19F, 1H and 13C NMR measurements. The carbocation is stable at room temperature for more than 2 weeks and was converted into the corresponding carbonate when reacted with water. 相似文献
11.
In the presence of catalytic amount of In(OTf)3 (10 mol%), a series of aldimines reacted with tetraallyltin in a 2:1 molar ratio to afford the corresponding homoallylic amines in good yields. The good atom efficiency was achieved under mild reaction conditions and a new protocol (allyl)4Sn/In(OTf)3 for simple imines was developed. 相似文献
12.
Previous publication showed that the stereochemistry of lithium aluminum hydride reduction of cyclic ketones can be evaluated by the use of an empirical equation, . This paper reports further test of this relationship in the new system of 2,2-dimethyl-4-t-butyl-cyclohexanone. Lithium aluminum hydride reduction of this ketone yields 95.6% trans-alcohol (lit., 95.9%) corresponding to D?(D?G*)H of 1.67 Kcal/mol. With methyllithium, the ketone formed 77.5% of trans-alcohol (D?(D?G*)D?fs = 0.67 Kcal/mol). These data give a calculated D?G* = 0.74 Kcal/mol which agrees well with the literature value of 0.87 or 0.28 Kcal/mol. Structural assignments of 2,2-dimethyl-4-t-butylyclohexanone, 1,2,2-trimethyl-cis- and trans-4-t-butylcyclohexanols by pmr spectroscopic method are also given. 相似文献
13.
Viacheslav A. Petrov 《Journal of fluorine chemistry》2004,125(4):531-536
It was demonstrated that the reaction of 2,2-bis(trifluoromethyl)oxirane (1) with variety of alcohols could be successfully carried out under phase transfer catalysis conditions using sodium or potassium hydroxide as a base. For example, reaction of CH3OH, C2H5OCH2CH2OH, HOCH2CH2OH with one or two moles of 1 in the presence of the catalyst [(C4H9)4N+HSO4−] gives the corresponding tertiary alcohols R[OCH2C(CF3)2OH]n (n=1 or 2) in 43-53% yield, along with some O[CH2C(CF3)2OH]2. Benzyl alcohol and phenol under similar conditions are less active, producing in the reaction with 1 the corresponding adducts ArOCH2C(CF3)2OH in 31-35% yield. Fluorinated alcohols, such as CF3CH2OH, ClCF2CH2OH, HCF2CF2CH2OH have much higher reactivity towards 1 giving ring opening products in 82-97% yield. Even in the reaction of hindered hexafluoro-iso-propanol the corresponding adduct was isolated in 43% yield. Surprisingly, the reaction of iso-propanol and epoxide 1, results in the formation of O[CH2C(CF3)2OH]2 as a major product, isolated in 56% yield. Possible mechanism for the formation of the last product was proposed. 相似文献
14.
An efficient synthesis of 2,2-dimethyl-2H-chromenes was accomplished by Pd(II)-catalyzed coupling and SiO2-promoted condensation of o-halophenols with 2-methyl-3-buten-2-ol (1,1-dimethylallyl alcohol) in one pot. The method is very general and can be useful for the synthesis of some natural 2,2-dimethyl-2H-chromenes. 相似文献
15.
16.
A novel synthesis of α,α-difluoro-γ-butyrolactones was realized by the alkaline hydrolysis of the adducts of ethyl iododifluoroacetate and alkenes. Ethyl iododifluoroacetate reacted with alkenes in the presence of sodium dithionite to give the addition products in 62-78% yields. The products were hydrolyzed in 10% aqueous sodium carbonate solution to give α,α-difluoro-γ-butyrolactones in 93-98% yields. 相似文献
17.
Masafumi Kobayashi Tetsuya Inoguchi Takashi Iida Takashi Tanioka Hiroshi Kumase Yasushi Fukai 《Journal of fluorine chemistry》2003,120(2):2838-110
Direct fluorination of 1,3-dioxolan-2-one with elemental fluorine was successfully carried out to provide 4-fluoro-1,3-dioxolan-2-one, which was expected as an additive for lithium ion secondary battery. 4-Fluoro-1,3-dioxolan-2-one was also further fluorinated with elemental fluorine to give three isomers of difluoro derivatives by the same methodology. Another topic is the preparation of trifluoromethanesulfonyl fluoride, an intermediate of lithium battery electrolyte, by the reaction of methanesulfonyl fluoride with elemental fluorine. The use of perfluoro-2-methylpentane as a solvent gave satisfactory selectivity of trifluoromethanesulfonyl fluoride. 相似文献
18.
The [Cu(acac)2]‐catalyzed reactions of several tertiary enaminones with three diazocarbonyl compounds, i.e., dimethyl diazomalonate, ethyl diazoacetoacetate, and ethyl diazoacetate, yielded amino‐ and additionally carbonyl‐substituted dihydrofurans, together with further furan derivatives. Due to the conjugation of α‐carbonyl/α‐Ph groups, reactions proceeded only via 1,5‐electrocyclization of corresponding keto‐ylides. On the other hand, in the absence of any α‐substituent, tertiary enaminone and ethyl diazoacetate, reacted via an accompanying mechanism by a push‐pull cyclopropane intermediate, to yield a 2,4‐dicarbonyl‐substituted furan in one step with moderate yield. 相似文献
19.
20.
《Tetrahedron》2014,70(51):9628-9634
New and practical acid-promoted domino bicyclization between 2,2-dihydroxyindene-1,3-dione and cyclic enaminones has been established for the formation of tetracyclic isochromeno[4,3-b]indoles under microwave heating. The present method simultaneously installs C–N, C–O, and C–C bonds, allowing direct assemble of functionalized isochromeno[4,3-b]indole skeleton with a wide diversity in substituents. The reaction features reliable scalability, flexibility of structural modification, and wide substrate scope as well as operational simplicity, and it can avoid time-consuming and costly syntheses, tedious work-up, and isolation of intermediate. 相似文献