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1.
[reaction: see text] Copper-mediated homocoupling of sterically hindered 2-(2,4,6-tri-tert-butylphenyl)-1-trialkylsilyl-2-phosphaethenyllithiums afforded 1,2-bis(trialkylsilyl)-3,4-diphosphacyclobutenes (1,2-dihydrodiphosphetenes) through a formal electrocyclic [2+2] cyclization in the P=C-C=P skeleton as well as 2-trimethylsilyl-1,4-diphosphabuta-1,3-diene. Reduction of 1,2-bis(trimethylsilyl)-3,4-diphosphacyclobutenes followed by quenching with electrophiles afforded ring-opened products, (E)-1,2-bis(phosphino)-1,2-bis(trimethylsilyl)ethene and (Z)-2,3-bis(trimethylsilyl)-1,4-diphosphabut-1-ene. The structures of the ring-opened products indicated E/Z isomerization around the C=C bond after P-P bond cleavage of 5, and the isomerization of the P-C=C skeleton. Ring opening of 1,2-bis(trimethylsilyl)-3,4-diphosphacyclobutenes affording (E,E)- and (Z,Z)-1,4-diphosphabuta-1,3-dienes was observed upon desilylation. 相似文献
2.
Walter Fink 《Helvetica chimica acta》1975,58(5):1464-1465
The reaction of Fe2(CO)9 with 1,2-bis(dimethylsilyl)benzene, 1,2,4,5-tetrakis(dimethylsilyl)benzene and vic-tetrakis(dimethylsilyl)benzene affords bis(silyl)chelate complexes of iron. 相似文献
3.
Mitsuo Ishikawa Ken-Ichi Nakagawa Makoto Kumada 《Journal of organometallic chemistry》1980,190(2):117-128
The photolysis of tris(trimethylsilyl)phenylsilane (I) in the presence of 1-hexyne, 3,3-dimethyl-1-butyne, trimethylsilylacetylene, 3-hexyne, 1-trimethylsilylpropyne, 1,2-bis(trimethylsilyl)acetylene and 2,2,5,5-tetramethyl-3-hexyne afforded the respective silacyclopropenes. The silacyclopropenes produced from monosubstituted acetylenes underwent photochemical isomerization to give disilanylacetylene derivatives, via a 1,2-hydrogen shift in the silacyclopropene ring. Irradiation of I in the presence of 3-hexyne, 1-trimethylsilylpropyne or 2,2,5,5-tetramethyl-3-hexyne, gave the corresponding silacyclopropenes which could be isolated by preparative GLC. The silacyclopropene from 1,2-bis(trimethylsilyl)acetylene, however, readily underwent thermal rearrangement to give [bis(trimethylsilyl)phenylsily] trimethylsilylacetylene via a 1,2-trimethylsilyl shift. This type of rearrangement was also found in the photochemical process. 相似文献
4.
1,2-Bis(trimethylsilyl)benzenes are key starting materials for the synthesis of benzyne precursors, Lewis acid catalysts, and certain luminophores. We have developed efficient, high-yield routes to functionalized 4-R-1,2-bis(trimethylsilyl)benzenes, starting from either 1,2-bis(trimethylsilyl)acetylene/5-bromopyran-2-one (2) or 1,2-bis(trimethylsilyl)benzene (1)/bis(pinacolato)diborane. In the first reaction, 5 (R = Br) is obtained through a cobalt-catalyzed Diels-Alder cycloaddition. The second reaction proceeds via iridium-mediated C-H activation and provides 8 (R = Bpin). Besides its use as a Suzuki reagent, compound 8 can be converted into 5 with CuBr(2) in i-PrOH/MeOH/H(2)O. Lithium-bromine exchange on 5, followed by the addition of Me(3)SnCl, gives 10 (R = SnMe(3)), which we have applied for Stille coupling reactions. A Pd-catalyzed C-C coupling reaction between 5 and 8 leads to the corresponding tetrasilylbiphenyl derivative. The bromo derivative 5 cleanly undergoes Suzuki reactions with electron-rich as well as electron-poor phenylboronic acids. 相似文献
5.
《Journal of organometallic chemistry》1991,402(2):C20-C22
The thermolysis of 1-mesityl-3-phenyl-1,2-bis(trimethylsilyl)-1-silacyclopropene at 280°C afforded 1-mesityl-3,3-dimethyl-4-phenyl-5-(trimethylsilyl)-1,3-disilacyclo-4-pentene and 1-mesityl-1,3-bis(trimethylsily)-1-silaindene. Similar thermolysis of 2-mesityl-2-(phenylethynel)hexamethyltrisilane produced the same products. 相似文献
6.
Direct trimethylsilylation of naphthalene under certain condition has been found to afford substitution as well as addition products: 1-and 2-trimethylsilylnaphtalene (I, II), 1-trimethylsilyl-1,4-dihydronaphthalene (III), trans-1,2-bis(trimethylsilyl)-1,2-dihydronaphthalene (IV-a) and its isomer (IV-b), and 1,2,4-tris(trimethylsilyl)-1,2-dihydronaphthalene (V). The configuration has been determined by nmr spectroscopy, and the possible reaction path was proposed. 相似文献
7.
W.P. Norris 《Tetrahedron》1972,28(7):1965-1972
Tetrakis(dimethylamino)ethylene reacts in methanol at 25° to give carbon-carbon bond cleavage, substitution of methoxyl for dimethylamino and addition of methanol to the double bond. The principal products are dimethylamine, dimethoxydimethylaminomethane and 1,1,2-trimethoxy-1,2-bis(dimethylamino)ethane. Minor products are methoxydimethylamino-N,N-dimethylacetamide, trimethylamine and dimethyl ether. An oxidation-reduction side reaction forms a very small amount of the radical cation of tetrakis(dimethylamino)ethylene. In the presence of sodium methoxide no carbon-carbon bond cleavage occurs and no radical cation is formed. When methanol is dissolved in tetrakis(dimethylamino)ethylene (methanol 1M), the principal products are 1,1,2-trimethoxy-1,2-bis(dimethylamino)ethane and dimethylamine with small amounts of tris(dimethylamino)methoxyethylene and 1,2-bis(dimethyl amino)-1,2-dimethoxyethylene. Tetrakis(dimethylamino)ethylene and water give dimethylamine and dimethylformamide. 相似文献
8.
Biphenyl-contained monomer of 1,4-bis[2-(3,4-epoxy cyclohexyl ethyl) dimethylsilyl] biphenyl(BP-Si H-EP) was prepared via hydrosilylation reaction of 1,4-bis(dimethylsilyl) biphenyl(BP-Si H) and 1,2-epoxy-4-vinylcyclohexane in the presence of Karstedt's catalyst. ~1H-NMR, ~(13)C-NMR and FTIR were used to characterize the structure of the obtained monomer. BP-Si H-EP was then cured by methyl hexahydrophthalic anhydride(Me HHPA) with 1-cyanoethyl-2-ethyl-4-methylimidazole as an accelerator. The polymerization behavior was studied by DSC. The results of DMA measurement demonstrate that the cured BP-Si H-EP/Me HHPA can maintain high storage modulus(1 GPa) in a wide range of temperature up to 176 °C. According to the damping factor curve of DMA, cured BP-Si H-EP/Me HHPA exhibits a high glass transition temperature(T_g) of 192 ° C, which is 20 ° C higher than that of cured 1,4-bis[2-(3,4-epoxy cyclohexyl ethyl)dimethylsilyl] benzene(DEDSB)/Me HHPA. TGA results show that cured BP-Si H-EP/Me HHPA has good thermal stability(T_(5% )= 339 ° C) due to the high heat-resistance of rigid biphenyl group. Moreover, the crosslinking density of cured BP-Si H-EP/Me HHPA should be lower than that of cured DEDSB/Me HHPA estimated from their chemical structures, which conflicts with the calculated results based on the rubber elasticity equation. The inconsistence indicates that the calculated crosslinking densities are not comparable, possibly owing to their differences in the rigidity of polymer chains and intermolecular interaction. 相似文献
9.
The metalation of selected oligobromobenzenes with lithium diisopropylamide (LDA) was investigated. 1,3-Dibromo-substituted benzenes were metalated without special precautions since the resultant 2,6-dibromophenyllithium intermediates are relatively stable under reaction conditions: corresponding benzaldehydes were obtained in good or moderate yields after subsequent quench with N,N-dimethylformamide (DMF). Aryllithium compounds derived from 1,4- and 1,2-dibromobenzene are much less stable, but they could be trapped by the in situ use of chlorotrimethylsilane. The one-pot metalation/disilylation of 1,4-dibromo- and 1,2-dibromobenzene afforded 1,4-dibromo-2,5-bis(trimethylsilyl)benzene and 2,3-dibromo-1,4-bis(trimethylsilyl)benzene, respectively. 相似文献
10.
Poly(o-phenyleneditelluride) 6 has been prepared by the reduction of 1,2-bis(trichlorotelluro)benzene obtained by treatment of 1,2-bis(trimethylsilyl)benzene with TeCl2. The reduction of 6 with NaBH4 in ethanol solution affords sodium benzene-1,2-ditellurolate, which, upon treatment with methylene bromide, forms benzo-1,3-ditellurole in 40–47% yield. Benzo-1, 3-ditellurole has also been synthesized in 18–20% yeild by the reaction of 1,2-bis(trimethylslyl)benzene with bis(trichlorotelluro)methane, with subsequent reduction of the product, 1,1,3,3-tetrachlorobenzo-1,3-ditellurole. 相似文献
11.
J. Pornet 《Journal of organometallic chemistry》1988,340(3):273-282
Alkyl -substituted 1,4-bis(trimethylsilyl)-2-alkynes react with electrophilic reagents to give silylated conjugated dienes, which result from a 1,2-shift of a trimethylsilyl group to a vinylic cationic center. 相似文献
12.
Synthesis, NMR Spectroscopic Characterization and Structure of Bis(1,2-dimethoxyethane-O,O′)barium Bis[1,3-bis(trimethylsilyl)-2-phenyl-1-aza-3-phosphapropenide] Barium-bis[bis(trimethylsilyl)phosphanide] 1 reacts with two equivalents of benzonitrile to give barium bis[1,3-bis(trimethylsilyl)-2-phenyl-1-aza-3-phosphapropenide]; the choice of the solvent determines whether a tris-(tetrahydrofuran)- or a bis(1,2-dimethoxyethane)-complex 2 can be isolated. 2 crystallizes from DME as red cuboids (monoclinic, C2/c, a = 1627.0(3), b = 1836.6(3), c = 1602.5(2) pm; β = 96.071(12)°; V = 4761.7(12); Z = 4; wR2 = 0.0851). The phosphorus atom displays a pyramidal surrounding in contrast to the planar coordination sphere of the nitrogen atom. In addition a twist within the P? C? N skeleton of the heteroallyl anion is observed. 相似文献
13.
Mitsuo Kira Takakazu Hino Yasushi Kubota Naoko Matsuyama Hideki Sakurai 《Tetrahedron letters》1988,29(52):6939-6942
Reduction of 1,1-bis(trimethylsilyl)ethylene by alkali metal led to the facile dimerization to the 1,1,4,4-tetrakis(trimethylsilyl)butane-1,4-diyl dianion which has been found to be utilized as a reagent for the Peterson reaction. 相似文献
14.
Reactions of 1,2-Bis(trimethylsilyl)imines with Selenium and Tellurium Halogenides The reactions of benzil-bis(trimethylsily)imine and phenanthrene-9,10-bis(trimethylsilyl)imine with SeOCl2, SeCl4 and TeCl4 are described. 相似文献
15.
The reactions of tris(acetonitrile)tricarbonylchromium 1 with trimethylsilyl derivatives 2–5 of phenalene, indene, 1,2-dihydronaphthalene and trans-β-methylstyrene gave products 10-13, respectively, containing no trimethylsilyl groups. The reactions of 1 with trimethylsilyl derivatives 6–8 of benzene, toluene and cycloheptatriene gave products 14–16, respectively, containing trimethylsilyl groups. The reaction of 1 with 1,2-bis(trimethylsily-1,2-dihydro)naphthalene 9 gave product 17 in which only trimethylsilyl at the allylic position was cleaved. Compound 10 crystallizes in the orthorhombic system, space group Pbca, with a = 12.228(4), b = 14.288(1), c = 15.128(3) Å, Z = 8, RF= 0.046, and Rw = 0.047. X-ray crystallographic data confirm that the Cr(CO)3 moiety is bonded to phenalene in a η6-mold. 相似文献
16.
A heptanuclear iron carbonyl cluster, [Fe(3)(CO)(11)(μ-H)](2)Fe(DMF)(4) (4), is found to be a highly efficient catalyst for the reduction of various carboxamides by 1,2-bis(dimethylsilyl)benzene (BDSB), which makes possible reducing the amount of the catalyst, shortening the reaction time, and lowering the reaction temperatures. 相似文献
17.
Anthony L. DiSalvo John H. Cornell 《Journal of polymer science. Part A, Polymer chemistry》1975,13(1):97-104
Representative aliphatic and aromatic polyurethanes undergo degradation upon treatment with hexamethyldisilazane (HMDS) at elevated temperatures. The course of the reaction is dependent on the nature of the polyurethane. Thus heating poly-[ethylene methylene bis(4-phenylcarbamate)] with HMDS in a sealed tube at 197°C gives high yields of 4,4′-diaminodiphenylmethane, trimethylisocyanatosilane, and 1,2-bis(trimethylsiloxyethane) along with lesser amounts of hexamethyldisiloxane, bis-(trimethylsilyl)carbodiimide, and ammonia. Under the same conditions, poly(ethylene N,N′-hexamethylenedicarboxylate) gives no diamine, but good yields of polyhexamethyleneurea and 1,2-bis(trimethylsiloxy)ethane together with smaller quantities of the other named products are obtained. In the course of this study, two novel routes to polyalkyleneureas were developed. For example, polyhexamethyleneurea is obtained in good yield by treatment of 1,6-hexanediamine with trimethyklisocyanatosilane at elevated temperatures in a sealed tube. The reaction of 1,1′-hexamethylenediurea with HMDS under these conditions results in formation of the same product. A mechanism rationalizing the foregoing results is proposed which involves initial nucleophilic attack by HMDS on the polyurethane to give an intermediate disilylated urea. Thermal decomposition of this intermediate by alternative routes would give the observed products. 相似文献
18.
Gun'ko VM Sheeran DJ Augustine SM Blitz JP 《Journal of colloid and interface science》2002,249(1):123-133
Silica gels Davisil 633 and 643, and fumed silica Cab-O-Sil HS-5 with grafted 3-aminopropyl dimethylsilyl (APDMS), butyl dimethylsilyl (BDMS), octadecyl dimethylsilyl (ODDMS), and trimethylsilyl (TMS) groups of different concentrations were studied using the nitrogen adsorption method. Changes in the textural and energetic characteristics of modified silicas depend on features of the oxide matrices and grafted OSC. 相似文献
19.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1982,38(11):1115-1122
The normal Raman spectra of trans-1,2-bis(4-pyridyl)ethylene and its dihydrochloride and dideuterochloride salts are reported. Frequency shifts observed upon salt formation and deuteration are utilized in the assignment of vibrational modes. Additional assignments are made by comparisons to other pyridine-containing molecules and trans-stilbene. Assignment of the normal Raman spectrum of trans-1,2-bis(4-pyridyl)ethylene is essential to interpretation of the surface Raman spectrum of this molecule reported elsewhere[1]. 相似文献
20.
Michele Daney Brigitte Labrande Rene Lapouyade Henri Bouas-Laurent 《Journal of organometallic chemistry》1978,159(4):385-399
The structure of 9-trimethylsilyl-9,10-dihydroanthracene (Me3SiDHA) has been studied by NMR; the coupling constants of the three 9,10 protons do not change at between 25 and 90°C (ABM spectrum; JAB }- 18.2; JAM ? 1.2; JBM ? 0.3 Hz in toluene-d8), indicating that the Me3Si group prefers the quasi axial position. In the presence of BuLi in THF, Me3SiDHA reacts with Me3SiCl to yield three new products: 9,9-bis(trimethylsilyl)-9,10-dihydroanthracene (IId) (major), (9,10-dihydroanthracen-9-yl)dimethylsilyl(trimethylsilyl)methane (V) and (9-trimethylsilyl-9,10-dihydroanthracen-9-yl)dimethylsilyl(trimethylsilyl)-methane (VI) together with the known 9,10-bis(trimethylsilyl)-9,10-dihydroanthracene (cis and trans). The carbanion of Me3SiDHA can also be alkylated (alkyl Me, Et, i-Pr) to the new 9,9-disubstituted derivatives: 9-Me3Si-9-alkyl-DHA.The formation of the carbanion of Me3SiDHA has been investigated and reveals a competition in the abstraction by the base of H9 and H10; the latter is less crowded but the 9-carbanion is stabilized by the vicinity of the silicon atom. The carbanion obtained from Me3SiDHA reacts exclusively at C(9) with D2O. A study of the alkylation of 9-trimethylsilyl-9-deuterio-9,10-dihydroanthracene shows that the generation of the 10-carbanion is followed by a 1,4 hydrogen rearrangement which yields the 9-carbanion. The mechanism is discussed and the roles of Me3Si and t-Bu are compared in the DHA series. 相似文献