- Catalyst-Controlled Stereoselective Barton–Kellogg Olefination
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Overcrowded alkenes are expeditiously prepared by the versatile Barton–Kellogg olefination and have remarkable applications as functional molecules owing to their unique stereochemical features. The induced stereodynamics thereby enable the controlled motion of molecular switches and motors, while the high configurational stability prevents undesired isomeric scrambling. Bistricyclic aromatic enes are prototypical overcrowded alkenes with outstanding stereochemical properties, but their stereocontrolled preparation was thus far only feasible in stereospecific reactions and with chiral auxiliaries. Herein we report that direct catalyst control is achieved by a stereoselective Barton–Kellogg olefination with enantio- and diastereocontrol for various bistricyclic aromatic enes. Using Rh2(S-PTAD)4 as catalyst, several diazo compounds were selectively coupled with a thioketone to give one of the four anti-folded overcrowded alkene stereoisomers upon reduction. Complete stereodivergence was reached by catalyst control in combination with distinct thiirane reductions to provide all four stereoisomers with e.r. values of up to 99:1. We envision that this strategy will enable the synthesis of topologically unique overcrowded alkenes for functional materials, catalysis, energy- and electron transfer, and bioactive compounds.
- Schmidt, Tanno A.,Sparr, Christof
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supporting information
p. 23911 - 23916
(2021/10/08)
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- COMPOUND FOR ORGANIC ELECTRONIC ELEMENT, ORGANIC ELECTRONIC ELEMENT USING THE SAME, AND AN ELECTRONIC DEVICE THEREOF
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The present invention relates to a compound for an organic electronic element. To the present invention, an organic electronic element having high luminous efficiency, low driving voltage, and high heat resistance can be provided, and color purity and lifetime of the organic electronic element can be improved.
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Paragraph 0360-0363
(2021/03/23)
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- Novel synthesis method of chlorolucanthone
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The invention discloses a novel synthesis method of chlorolucanthone, and belongs to the technical field of chemical engineering. The method comprises the following steps: firstly, adding a sodium hydrosulfide solution into a hydrogen sulfide generator, then dropwise adding an acid into the hydrogen sulfide generator, and guiding generated gas into a preheated pipeline reactor; pumping preheated p-dichlorobenzene into the pipeline reactor, reacting the p-dichlorobenzene with hydrogen sulfide gas, cooling a reaction product to obtain liquid and gas, and rectifying and purifying the liquid to obtain mercaptochlorobenzene; secondly, adding a reaction solvent and an alkali into a flask, stirring, adding mercaptochlorobenzene and o-chlorobenzoic acid, carrying out a reflux reaction, and carrying out aftertreatment after the reaction is finished so as to obtain an intermediate 2-carboxyl-4'-chlorodiphenyl sulfide; and finally, adding 2-carboxyl-4'-chlorodiphenyl sulfide into concentrated sulfuric acid, carrying out an intramolecular cyclization dehydration reaction, and purifying after the reaction is ended so as to obtain the target product. The method disclosed by the invention is simple and convenient to operate, mild in reaction condition, clean and environment-friendly, and high in product yield and purity.
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- Carboxyl radical-assisted 1,5-aryl migration through Smiles rearrangement
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We report herein, a silver(i)-catalyzed Smiles rearrangement of 2-aryloxy- or 2-(arylthio)benzoic acids to provide aryl-2-hydroxybenzoate or aryl-2-mercaptobenzoate dimer, respectively, through 1,5-aryl migration from oxygen or sulfur to carboxylate oxygen. Mechanistically, the aryl ether moiety undergoes an intramolecular ipso attack by the carboxyl radical followed by a C-O or C-S bond cleavage. Aryl-2-mercaptobenzoates undergo oxidative dimerization through a thiol moiety in situ.
- Hossian, Asik,Jana, Ranjan
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supporting information
p. 9768 - 9779
(2016/10/31)
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- A mild and facile synthesis of aryl and alkenyl sulfides via copper-catalyzed deborylthiolation of organoborons with thiosulfonates
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An efficient deborylthiolation of aryl- and alkenylborons with thiosulfonates has been achieved under mild conditions using a copper catalyst. All steps of the experimental process were free from unpleasant odors. The mild reaction conditions as well as ready availability of boron compounds and thiosulfonates enabled easy access to an array of sulfides, including those bearing sensitive functional groups.
- Yoshida, Suguru,Sugimura, Yasuyuki,Hazama, Yuki,Nishiyama, Yoshitake,Yano, Takahisa,Shimizu, Shigeomi,Hosoya, Takamitsu
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p. 16613 - 16616
(2015/11/25)
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- Recyclable heterogeneous supported copper-catalyzed coupling of thiols with aryl halides: base-controlled differential arylthiolation of bromoiodobenzenes
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Alumina-supported copper sulfate efficiently catalyzes the 5-arylation of aromatic, heteroaromatic and aliphatic thiols with aryl as well as heteroaryl halides under aerobic, ligand-free conditions. This protocol provides an easy access to a variety of thioethers as well as unsymmetrical bis-thioethers by base-controlled differential coupling of thiols with iodo- and bromo-substituents in an aromatic halide. The catalyst is inexpensive, non-air sensitive, environmentally friendly and recyclable.
- Bhadra, Sukalyan,Sreedhar, Bojja,Ranu, Brindaban C.
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experimental part
p. 2369 - 2378
(2009/12/28)
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- Process for the preparation of 2-arylthiobenzoic acids
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A process for the preparation of 2-arylthiobenzoic acids which are useful as intermediates in producing thioxanthene compounds comprises reacting by reacting lithium 2-chlorobenzoate of the formula STR1 with lithium thiophenoxide of the formula STR2 wherein R is alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, trifluoromethyl, hydrogen, fluorine, chlorine or nitro and n is 1, 2, 3 or 4.
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- Preparation of 2-chloro-thioxanthone
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The invention relates to 2-(4'-chloro-phenylthio)-benzonitrile, to its process of preparation and to its use for preparing 2-chlorothioxanthone. 2-Chloro-thioxanthone prepared from the compound of the invention is useful as a photoinitiator for the reticulation of synthetic resins and as an intermediate for preparing pharmaceuticals.
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- Method of preparing aryloxybenzoic and arylthiobenzoic acids
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Novel process for preparing aryloxybenzoic and arylthiobenzoic acids by reacting 2-chlorobenzoic acid with substituted phenols or thiophenols in the presence of an alkali metal iodide and a base.
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