- 9-Silyl(-Germyl,-Stannyl) Substituted Derivatives of 1-(9-Fluorenyl)-germatranes. Synthesis, Characterisation, and Crystal Structures
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9-Trimethylsilyl- and 9-trimethylgermyl substituted derivatives of 1-(9-fluorenyl)germatranes C13H8(R)Ge(OCH2CH2)3N (1 - 3) (1: R = H; 2: R = Me3Si; 3: R = Me3Ge) were prepared by the reaction of 9-tribromogermyl derivatives of fluorene C13H8(R)GeBr3 (4 - 6) with N(CH2CH2OSnAlk3)3 (7: Alk = Et; 8: Alk = Bu). 1-(9-Trimethylstannyl-9-fluorenyl)germatrane (14) was synthesised by the reaction of the germatrane (1) with Me3SnNMe2. Formulas and structures were established by elemental analyses, (1H, 13C) NMR spectroscopy and mass spectrometry; crystal structures of 2 and 14 are reported.
- Zaitseva, Galina S.,Karlov, Sergey S.,Siggelkow, Bettina A.,Avtomonov, Evgeni V.,Churakov, Andrei V.,Howard, Judith A.K.,Lorberth, Joerg
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- Carbo-quinoids: Stability and reversible redox-proaromatic character towards carbo-benzenes
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The carbo-mer of the para-quinodimethane core is stable within in a bis(9-fluorenylidene) derivative. Oxidation of this carbo-quinoid with MnO2 in the presence of SnCl2and ethanol affords the corresponding p-bis(9-ethoxy-fluoren-9-yl
- Cocq, Kvin,Maraval, Valrie,Saquet, Alix,Poidevin, Corentin,Lepetit, Christine,Chauvin, Remi,Saffon-Merceron, Nathalie
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- METHOD FOR PRODUCING ORGANOSILICON COMPOUND USING HALOSILANE AS RAW MATERIAL
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PROBLEM TO BE SOLVED: To provide a novel method for producing an organosilicon compound. SOLUTION: The method for producing an organosilicon compound includes a reaction step (I) of reacting a halosilane represented by formula (a) with a compound containing a hydrocarbon group represented by formula (b) in the presence of an organic base to generate an organosilicon compound represented by formula (c). (In the formula (I), n is an integer of 0-3; each R1 independently represents a hydrogen atom or a C1-20 hydrocarbon group which may contain a heteroatom; X represents a bromo group (-Br) or a chloro group (-Cl); and R2 represents a compound containing a hydrocarbon group.) SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2020,JPOandINPIT
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Paragraph 0048-0049; 0055
(2019/12/10)
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- Migratory Insertion of Carbenes into Au(III)-C Bonds
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Migratory insertion of carbon-based species into transition-metal-carbon bonds is a mechanistic manifold of vast significance: it underlies the Fischer-Tropsch process, Mizoroki-Heck reaction, Ziegler-Natta and analogous late-transition-metal-catalyzed olefin polymerizations, and a number of carbonylative methods for the synthesis of ketones and esters, among others. Although this type of reactivity is well-precedented for most transition metals, gold constitutes a notable exception, with virtually no well-characterized examples known to date. Yet, the complementary reactivity of gold to numerous other transition metals would offer new synthetic opportunities for migratory insertion of carbon-based species into gold-carbon bonds. Here we report the discovery of well-defined Au(III) complexes that participate in rapid migratory insertion of carbenes derived from silyl- or carbonyl-stabilized diazoalkanes into Au-C bonds at temperatures ≥ -40 °C. Through a combined theoretical and experimental approach, key kinetic, thermodynamic, and structural details of this reaction manifold were elucidated. This study paves the way for homogeneous gold-catalyzed processes incorporating carbene migratory insertion steps.
- Zhukhovitskiy, Aleksandr V.,Kobylianskii, Ilia J.,Wu, Chung-Yeh,Toste, F. Dean
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supporting information
p. 466 - 474
(2018/03/21)
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- Palladium-Catalyzed Formal [4 + 1] Annulation via Metal Carbene Migratory Insertion and C(sp2)-H Bond Functionalization
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A highly efficient and operationally simple palladium-catalyzed formal [4 + 1] annulation reaction has been developed. The reaction is featured by the formation of two different C-C bonds on a carbenic center. It represents a concise method for the synthesis of a wide range of polycyclic aromatic hydrocarbons (PAHs) and 1H-indenes with easily available (trimethylsilyl)diazomethane as the carbene source. Metal carbene migratory insertion and C(sp2)-H bond activation are proposed as the key steps in this transformation. The reaction further demonstrates the versatility of the carbene-based coupling in combination with various transition-metal-catalyzed transformations.
- Xu, Shuai,Chen, Ri,Fu, Zihao,Zhou, Qi,Zhang, Yan,Wang, Jianbo
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p. 1993 - 1997
(2017/08/14)
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- Peterson olefination: Unexpected rearrangement in the overcrowded polycyclic aromatic ene series
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An attempted synthesis of the angularly annelated 9-(11′-benzo[a] fluoren-11′-ylidene)-9H-fluorene (3) through a Peterson olefination reaction between (9H-fluoren-9-yl)trimethylsilyl anion (5a) and 11H-benzo[a]fluoren-11-one (6) led to the linearly annelated 9-(11′-benzo[b]fluoren-11′-ylidene)-9H-fluorene (4), due to an unexpected rearrangement. The proposed mechanism of the rearrangement is illustrated. The core of the mechanism is an intramolecular Haller-Bauer cleavage of the naphthyl C11a′-C11′ bond in the β-oxysilane anion 11 (formed from 5a and 6) to give the 1-naphthyl anion (E)-12, followed by E/Z isomerization to (Z)-12 and by proton migration to give the 3-naphthyl anion (Z)-14. The intramolecular nucleophilic addition of the naphthyl anion at C-3′ of (Z)-14 to the carbonyl carbon gives the β-oxysilane anion 15, a benzo[b]fluorenylidene derivative. The mechanism is supported by the results of DFT calculations. The synthesis of 3 was achieved by application of Barton's double extrusion diazo-thione coupling method.
- Assadi, Naela,Pogodin, Sergey,Agranat, Israel
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experimental part
p. 6773 - 6780
(2011/12/21)
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- Antiaromatic spacer-bridged bisfluorenyl dications generated by superacid induced ionization
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Derivatives of the dication of tetrabenzo[5.5]fulvalene were prepared with phenyl and ethynyl spacers through ionization of the appropriate bis-methylethers. The antiaromaticity shown by the parent dication was demonstrated for these dications with spacer
- Dahl, Bart J.,Mills, Nancy S.
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supporting information; experimental part
p. 10179 - 10186
(2009/02/03)
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- Dications of fluorenylidenes. The relationship between redox potentials and antiaromaticity for meta- and para-substituted diphenylmethylidenefluorenes
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Electrochemical oxidation of meta-substituted diphenylmethylidenefluorenes (3a-g) results in the formation of fluorenylidene dications that are shown to be antiaromatic through calculation of the nucleus independent chemical shift (NICS) for the 5- and 6-
- Mills, Nancy S.,Tirla, Cornelia,Benish, Michele A.,Rakowitz, Amber J.,Bebell, Lisa M.,Hurd, Caroline M. M.,Bria, Anna L. M.
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p. 10709 - 10716
(2007/10/03)
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- Crystal, molecular, and electronic structure of 9,9′-bis(trimethylsilyl)fluorene
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The crystal and molecular structure of 9,9′-bis(trimethylsilyl)fluorene (1) has been determined by X-ray diffraction. The crystal of (1) is orthorhombic, space group Pnma with unit cell dimensions: a = 16.906(2) ?, b = 13.8080(10) ?, c = 8.1690(10) ?, α = β = γ = 90°. The silicon atoms are in a slightly distorted tetrahedral environment with C-Si-C bond angles in the range 107.13°-112.49°. A notable feature of the molecular structure is the significant deviation of the Sil-C9-Si2 angle (118.9°) from the normal tetrahedral value. This behaviour is attributed mainly to some intramolecular CH...π interactions.
- Silaghi-Dumitrescu, Ioan,Cretiu, Gabriela,Silaghi-Dumitrescu, Luminita,Haiduc, Ionel,Toscano, Alfredo,Cea-Olivares, Raymundo
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p. 289 - 295
(2007/10/03)
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- Dications of Fluorenylidenes. Electronic Effects on the Paratropicity/Antiaromaticity of 2,7-Disubstituted Fluorenyl Cations
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Oxidation of 2,7-disubstituted tetrabenzo[5.5]fulvalene derivatives 1a-d resulted in the formation of dications which are fluorenyl cations linked by a single bond. These fluorenyl cations exhibit significant paratropicity in the 1H NMR spectrum, which is attributed to an antiaromatic ring current. Interaction of the perpendicular ring systems is evident in the upfield shift of carbons a and a', presumably due to σ-p donation. The lack of variation in the upfield shift of carbons a and a', compared to previously reported systems, is attributed to the similarities of the geometries of 1a-d2+. Substitution at a remote site affects the antiaromaticity of the unsubstituted fluorenyl cation, but the nature of the effect of the substituent is not understood. Direct substitution on the fluorenyl cation by substituents which increase electron density, either through inductive π polarization or through resonance, cause a paratropic shift in the probe proton.
- Mills, Nancy S.,Burns, Ellen E.,Hodges, Jonathan,Gibbs, Jennifer,Esparza, Edward,Malandra, James L.,Koch, Josh
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p. 3017 - 3022
(2007/10/03)
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- Unverbrueckte fluorenylkomplexe des typs (C5H5)(9-R-C13H8)ZrCl2 (R = Me3Si, Alkyl, Aryl): Synthese, charakterisierung und anwendung als katalysatoren bei der homogenen olefinpolymerisation
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The reaction of various 9-substituted fluorene compounds (9-R-C13H9) (R = Me3Si, alkyl, aryl) (1a-i) with butyllithium followed by treatment with (C5H5)ZrCl3 leads to unbridged fluorenyl complexes of the type (C5H5)(9-R-C13H8)ZrCl2 (2a-i). In combination with methylaluminoxane, complexes 2a-i show a high catalytic activity as homogeneous ethylene polymerization catalysts. Compounds 2c (R = iPr), 2d (R = cyclohexyl), and 2e (R = tBu) were characterized by X-ray structure analyses.
- Schmid, Michael A.,Alt, Helmut G.,Milius, Wolfgang
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- Cyclopentadiene type compounds and method for making
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New fluorenyl silane compounds and method for their production are disclosed. The fluorenyl compounds have the formula STR1 wherein Z is a substituted or unsubstituted fluorenyl radical and Z' is a substituted or unsubstituted cyclopentadienyl-type radical or a halogen.
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- Cyclopentadiene type compounds and method for making
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Processes are disclosed for preparing compounds of the formula Z--R--Z where each Z can be selected from cyclopentadienyl type radicals such as substituted or unsubstituted cyclopentadienyl, indenyl, fluorenyl or tetrahydroindenyl or where one Z is Cl, Br, or I by reacting specific Z precursors with a dihaloalkylene compound. Also new cyclopentadienyl-type compounds are disclosed.
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- Ion Pair Carbon Acidities of Some Silanes in Tetrahydrofuran
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The relative solvent-separated ion pair (SSIP) lithium acidity (pKLi/THF) and contact ion pair (CIP) cesium acidity (pKCs/THF) were obtained for 9-fluorenyltrimethylsilane (1) (21.3, 21.6, respectively) and 9-fluorenyl-tert-butyldimethylsilane (2) (20.3, 20.6, respectively) in THF.Values for pKCs/THF were determined at 25 deg C for (p-biphenylylmethyl)-tert-butyldimethylsilane (3), 35.4, benzyltrimethylsilane (4), 37.5, α,α-bis(trimethylsilyl)toluene (5), 34.1, 2-(trimethylsilyl)-1,3-dithiane (6), 33.5, (trimethylsilyl)acetonitrile (7), 28.8, and tris(trimethylsilyl)methane (8), 36.8.Some thermodynamic parameters were determined by measurements at other temperatures, and some ionic acidities (pK(FI)) were determined by conductivity studies.Carbanion stabilization by these silyl substituents varies from about 1 to over 3 pK units in different systems. 9,9-Bis(trimethylsilyl)fluorene (9) was found to undergo silyl transfer on treatment with various carbanions, but this reaction is slower than proton transfer.
- Streitwieser, Andrew,Xie, Linfeng,Wang, Peng,Bachrach, Steven M.
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p. 1778 - 1784
(2007/10/02)
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- Synthesis of gem-9,9-Dilithiofluorene by Thermal Rearrangement
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The synthesis of an aromatic gem-dilithiumsubstituted fluorene by thermal rearrangement is described.
- Chauhan, Harendra P.S.,Kawa, Hajimu,Lagow, Richard J.
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p. 1632 - 1633
(2007/10/02)
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- Substituent Effects on Exited-State Efficiencies: Thermolysis of 3,3-(2,2'-Biphenyldiyl)-4-methyl-4-aryl-1,2-dioxetanes
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Triplet and singlet ketone efficiencies was determined for the thermolysis of a series of nine 3,3-(2,2'-biphenyldiyl)-4-methyl-4-aryl-1,2-dioxetanes, where substituent changes were made in the para and meta positions of the aryl group.Triplet efficiencies (αT), which were determined by trans-stilbene isomerization, ranged from 2.0percent (Ar=p-BrC6H4) to 19.0percent (Ar=C6H5) and the best linear free energy correlation was with ET1(ArCOCH3):log percent αT=(0.518 +/- 0.079)ET1(ArCOCH3)-36.62 +/- 5.73, Sy*x = +/- 0.144, which corresponds to +/- 1.4percent in percent αT.Since no light enhancement resulted upon addition of 9,10-dibromoanthracene, it was concluded that the intercepted triplet ketone product was fluorenone.The results were considered in terms of a triplet ketone exciplex (Scheme I) and equilibrating solvent caged encounter complexes (Scheme II).The singlet efficiencies for all members in the series were essentially constant (percentαS1 = 0.17percent).The chemiluminescent (CL) emission spectra of dioxetanes, where Ar = C6H5 and m-BrC6H4, match the fluorescence spectrum of fluorenone.In addition, the CL emission is not enhanced upon nitrogen purging.From a consideration of activation parameters and ρ reaction constants, a 1,4-dioxy biradical decomposition route for these dioxetanes appears most likely.
- Richardson, William H.,Thomson, Stephen A.
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p. 1803 - 1810
(2007/10/02)
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- Preparation of sulfines by alkylidenation of sulfur dioxide using α-silyl carbanions
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The synthesis of sulfines 4 from a series of active methylene compounds is described.Deprotonation, followed by silylation, gives the trimethylsilyl compounds 2.Subsequent deprotonation to α-silyl carbanions and treatment with an excess of sulfur dioxide
- Porskamp, P. A. T. W.,Leij, M. van der,Lammerink, B. H. M.,Zwanenburg, B.
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p. 400 - 404
(2007/10/02)
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- REACTIVITY OF CARBANIONS. XIV. KINETICS OF THE ALKYLATION OF CARBANIONS OF THE FLUORENYL TYPE AND THEIR ION PAIRS BY BUTYL BROMIDE
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The reaction rate constants were determined for the free carbanions and their ion pairs in the reaction of the lithium and cesium salts of 9-cyano-, 9-methoxycarbonyl-, 9-phenyl-, 9-triphenylmethyl-, 9-trimethylsilyl-, 9-benzyl-, 9-methyl-, 9-tert-butyl-, 2-cyano-, 2-bromo-, 2-methyl-, and 2-dimethylaminofluorenes, fluorene, 1-azafluorene, 3-methyl-2-azafluorene, 1,2-benzofluorene, and fluoradene with butyl bromide in dimethoxyethane at 25 gradC.The obtained data can be used as the basis for the creation of a scale of relative nucleophilicity in the carbanions.
- Solov'yanov, A. A.,Beletskaya, I. P.,Reutov, O. A.
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p. 1592 - 1603
(2007/10/02)
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