- Catalytic B-C Coupling by Si/B Exchange: A Versatile Route to π-Conjugated Organoborane Molecules, Oligomers, and Polymers
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Conjugated organoboranes have emerged as attractive hybrid materials for optoelectronic applications. Herein, a highly efficient, environmentally benign catalytic B-C bond formation method is presented that uses organosilicon compounds, dibromoboranes, and the metal-free organocatalyst Me3SiNTf2. This Si/B exchange approach has been successfully applied to the synthesis of arylborane molecules 4a-c, oligomers 8a,b, and polymers 8a′,b′. Photophysical investigations, supported by TD-DFT calculations, reveal highly effective π-conjugation in thienyl- and furylborane species; the latter are also highly emissive.
- Lik, Artur,Fritze, Lars,Müller, Lars,Helten, Holger
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- Synthesis of new silylated sulfur-containing heterocycles through thionation of bis(acylsilanes)
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The thionation of bis(acylsilanes) with spacers of variable size with hexamethyldisilathiane under cobalt(II) chloride or trimethylsilyl triflate catalysis affords 2,5-bis(trialkylsilyl)-thiophenes, 2,6-bis(trialkylsilyl)-4H- thiopyrans and 2,7-bis(trialkylsilyl)-4,5-dihydrothiepine generally along with a minor amount of the corresponding oxo analogue. The synthesis of both symmetrical and unsymmetrical bis(trialkylsilyl) derivatives was achieved.
- Bouillon, Jean-Philippe,Capperucci, Antonella,Portella, Charles,Degl'Innocenti, Alessandro
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- First synthesis of 1,4-bis(acylsilanes)
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1,4-Bis(acylsilanes) were prepared by substitution of 1,2-bis(triflates) with 2-lithio-2-trimethylsilyl- 1,3-dithiane or by silylation of 1,2- bis([1,3]dithian-2-yl)ethane and dethioketalization with methyl iodide or mercuric salts. The reaction with 1,2-dihalogenated alkanes gave dehydrodimers of 2-trialkylsilyl-1,3-dithianes. The cyclodehydration of the 1,4-bis(trialkylsilyl)- 1,4-butanediones gave 2,5-bis(trialkylsilyl) furanes.
- Saleur, Damien,Bouillon, Jean-Philippe,Portella, Charles
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- SILYLATION OF AROMATIC HETEROCYCLES BY DISILANES USING POTASSIUM ALKOXIDE CATALYSTS
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The present invention describes chemical systems and methods for silylating heteroaromatic organic substrates, said system consisting essentially of a mixture of (a) at least one organodisilane and (b) at least alkoxide base, preferably a potassium alkoxide base, and said methods comprising contacting a quantity of the organic substrate with a mixture consisting essentially of (a) at least one organodisilane and (b) at least one alkoxide base, preferably a potassium alkoxide, under conditions sufficient to silylate the heteroaromatic substrate.
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Paragraph 0133
(2016/07/05)
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- Synthesis of symmetrical and unsymmetrical 2,5-bis(trialkylsilyl)furans and 2,6-bis(trialkylsilyl)-4H-pyrans from 1,4- and 1,5-bis(acylsilanes)
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2,5-Bis(trialkylsilyl)furans and 2,6-bis(trialkylsilyl)-4Hpyrans have been synthesized by cyclodehydration of 1,4- and 1,5-bis(acylsilanes) under p-toluenesulfonic acid catalysis. The 1,4-bis(acylsilanes) have been prepared from 1,2-bis(1,3-dithian-2yl)ethane according to the reaction sequence metallation-silylationdethioketalization. The 1,5-bis(acylsilanes) have been prepared from 1,3-bis(1,3-dithian-2-yl)propane by a similar strategy or from a S(N) reaction of 1,3-dihalopropanes with 2-trialkylsilyl-2-lithio- 1,3dithiane and deprotection. The method allows efficient preparation of symmetrical as well as unsymmetrical bis(silylated) heterocycles.
- Bouillon, Jean-Philippe,Saleur, Damien,Portella, Charles
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p. 843 - 849
(2007/10/03)
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- High-yield electrosynthesis of furylchlorosilanes, silyl and silanylene furans
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The intensiostatic sacrificial anode technique proved to be efficient for the silylation of 2-bromo- and 2,5-dibromofurans with trimethylchlorosilane and diorganodichlorosilanes with high selectivity and versatility not accessible by pure chemical routes. Furylsilanes, bromofurylsilanes, bis(furyl)silanes, bis(bromofuryl)silanes, furylchlorosilanes, bis(silyl and chlorosilyl)furans, poly[(silanylene)furylene] oligomers and [14]dimethylsila-2,5-furanocalixarene were obtained in good to high yields.
- Moreau, Carole,Serein-Spirau, Francoise,Bordeau, Michel,Biran, Claude
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p. 147 - 154
(2007/10/03)
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- Activation of C-H Bonds of Heterocyclic and Alicyclic Compounds Using Calcium Atom
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Calcium atoms have been inserted into C-H bonds of heterocyclic (furans and thiophene) and alicyclic compounds (cyclohexanes and cyclopentane) to give the corresponding organocalcium hydrides.The organocalcium hydrides thus produced reacted with trimethylchlorosilane to give trimethylsilyl-substituted heterocyclic and alicyclic compounds, and a reduced product (trimethylsilane).
- Mochida, Kunio,Kojima, Kenji,Yoshida, Yasuhiro
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p. 2255 - 2256
(2007/10/02)
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- Regiospecific Synthesis of Aryl(2-furyl)iodonium Tosylates, a New Class of Iodonium Salts, from arenes and 2-(Trimethylsilyl)furans in Organic Solvents
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The treatment of 2,5-bis(trimethylsilyl)furan with various arenes (ArI(OH)OTs) in acetonitrile/ methanol has been found to give aryliodonium tosylates in yields ranging from 62percent to 80percent.With 2-methyl-5-(trimethylsilyl)furan as the substrate, aryl(5-methyl-2-furyl)iodonium tosylates are likewise obtained in yields ranging from 61percent to 74percent.The reactions of arenes with 2-(trimethylsilyl)furan in methanol give aryl(2-furyl)iodonium tosylates in much lower yield (9-23percent) and are accompanied by the reductive decomposition of the hypervalent organoiodine component.To our knowledge, these are the first reported examples of aryl(furyl)iodonium salts.
- Carman, Carol S.,Koser, Gerald F.
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p. 2534 - 2539
(2007/10/02)
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- RADICAL IONS 49. Redox Reactions of some Thiphene Derivatives
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Trimethylsilyl- and cyano-substituted thiophenes can be reduced in THF using potassium and the resulting radical anions can be characterized by their electron spin resonance spectra.Attempts to oxidize thiophene derivatives with low first ionization potentials to their radical cations using the ALCl3/H2CCl2 oxidizing system failed except for dithienyldisulfide, the radical cation of which rearranges under the reaction conditions to the one of dithieno-p-dithiin.The photoelectron and electron spin resonance spectroscopic assignments are supported by MNDO as well as parametrized HMO calculations.
- Bock, H.,Roth, B.
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p. 211 - 224
(2007/10/02)
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