1578-33-2Relevant academic research and scientific papers
Synthesis of the spirocyclic core of the prunolides using a singlet oxygen-mediated cascade sequence
Sofikiti, Nikoletta,Tofi, Maria,Montagnon, Tamsyn,Vassilikogiannakis, Georgios,Stratakis, Manolis
, p. 2357 - 2359 (2005)
(Chemical Equation Presented) A highly efficient and rapid four-step synthesis of the bis-spiroketal core of the prunolide natural products, starting from furan itself, is described. The key step and culmination of the synthesis, responsible for zipping up the spirocyclic core, is a singlet oxygen-orchestrated cascade sequence in which a double photooxygenation of a 1,2-difuryl alkene precursor precedes dehydration and spirocyclization to furnish the intact prunolide core.
Synthesis of C1-substituted 7-oxanorbornadienes
Raheem, Mohammed-Abdul,Tam, William
, p. 260 - 267,8 (2013)
7-Oxanorbornadienes are valuable synthetic intermediates as they can serve as general templates to create highly substituted ring systems. However, to date, only very few C1-substituted 7-oxanorbornadienes have been synthesized and can be found in the literature. In this article, synthesis of some C1-substituted 7-oxanorbornadienes was achieved by the Diels-Alder reaction between 2-substituted furans and dimethylacetylene dicarboxylate. Moderate to good yields (13-85%) of the Diels-Alder reactions were observed. These C1-substituted 7-oxanorbornadienes will find applications as valuable synthetic intermediates and are useful in the studies of transition-metal-catalyzed reactions.
Catalytic B-C Coupling by Si/B Exchange: A Versatile Route to π-Conjugated Organoborane Molecules, Oligomers, and Polymers
Lik, Artur,Fritze, Lars,Müller, Lars,Helten, Holger
supporting information, p. 5692 - 5695 (2017/05/04)
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.
SILYLATION OF AROMATIC HETEROCYCLES BY DISILANES USING POTASSIUM ALKOXIDE CATALYSTS
-
Paragraph 0133, (2016/07/05)
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.
CO2 Conversion into Esters by Fluoride-Mediated Carboxylation of Organosilanes and Halide Derivatives
Frogneux, Xavier,Von Wolff, Niklas,Thuéry, Pierre,Lefèvre, Guillaume,Cantat, Thibault
supporting information, p. 2930 - 2934 (2016/03/25)
A one-step conversion of CO2 into heteroaromatic esters is presented under metal-free conditions. Using fluoride anions as promoters for the C-Si bond activation, pyridyl, furanyl, and thienyl organosilanes are successfully carboxylated with CO2 in the presence of an electrophile. The mechanism of this unprecedented reaction has been elucidated based on experimental and computational results, which show a unique catalytic influence of CO2 in the C-Si bond activation of pyridylsilanes. The methodology is applied to 18 different esters, and it has enabled the incorporation of CO2 into a polyester material for the first time. Metal free! A novel methodology is described to convert CO2 into heteroaromatic esters in the presence of organosilanes and organic halides using fluoride anions as promoters for the C-Si bond activation (see scheme). CO2 exhibits a unique catalytic influence in the C-Si bond cleavage of pyridylsilanes, serving as a traceless activator.
Protecting-Group-Free Enantioselective Synthesis of (-)-Pallavicinin and (+)-Neopallavicinin
Huang, Bin,Guo, Lei,Jia, Yanxing
supporting information, p. 13599 - 13603 (2015/11/16)
The first enantioselective synthesis of (-)-pallavicinin and (+)-neopallavicinin has been achieved in 15 steps. The described synthesis avoids protecting-group manipulations by synthesis designs predicated on highly chemo- and stereoselective transformations. Highlights of the synthesis include a palladium-catalyzed enantioselective decarboxylative allylation to form the chiral all-carbon quaternary stereocenter, a palladium-catalyzed oxidative cyclization to assemble the [3.2.1]-bicyclic moiety, and an unprecedented LiBHEt3-induced fragmentation/protonation of an α-hydroxy epoxide to form the α-furan ketone with the desired configuration.
HETEROCYCLIC AMIDES AS ROCK INHIBITORS
-
Page/Page column 81, (2011/10/03)
The present invention relates to new kinase inhibitors of formula (I), more specifically ROCK inhibitors, compositions, in particular pharmaceuticals, comprising such inhibitors, and to uses of such inhibitors in the treatment and prophylaxis of disease. In particular, the present invention relates to new ROCK inhibitors, compositions, in particular pharmaceuticals, comprising such inhibitors, and to uses of such inhibitors in the treatment and prophylaxis of disease. In addition, the invention relates to methods of treatment and use of said compounds in the manufacture of a medicament for the application to a number of therapeutic indications including sexual dysfunction, inflammatory diseases, ophthalmic diseases and Respiratory diseases.
Gold catalysis: benzanellation versus alkylidenecyclopentenone synthesis
Hashmi, A. Stephen K.,W?lfle, Michael
supporting information; experimental part, p. 9021 - 9029 (2009/12/08)
A series of different furan-yn-ols were prepared by a three-step sequence. Their reaction with Gagosz's catalyst Ph3PAuNTf2 depends strongly on the substitution pattern of the substrate and the quality of the leaving group. Benzofurans, alkylidenecyclopentenones or Meyer-Schuster type products can be obtained. Improving the leaving group quality leads to the preferred formation of benzofurans.
Gold catalysis contra platinum catalysis in hydroarylation contra phenol synthesis
Hashmi, A. Stephen K.,Kurpejovi?, Elzen,Frey, Wolfgang,Bats, Jan W.
, p. 5879 - 5885 (2008/02/02)
Three silylated γ-alkynylfurans were prepared and subjected to both gold and platinum catalysts. The TMS- and the TBDMS-substituted furans reacted. With AuCl3 and the binuclear [(Ph3PAu)2Cl][BF4] catalyst a hydroarylation of the alkyne was observed. Na[AuCl4] gave phenols as the product, but these were formed only after in situ desilylation of the starting material by the gold catalyst and thus the wrong isomer dominated. Only with PtCl2(MeCN)2 phenols with a silyl group were formed. The TBDPS-substituted furan failed to react. Two alkynylsilanes were synthesized, but they also failed to react.
Fluoronaphthalene building blocks via arynes: A solution to the problem of positional selectivity
Masson, Eric,Schlosser, Manfred
, p. 4401 - 4405 (2007/10/03)
When 3-fluoro- and 3-chloro-1,2-didehydrobenzenes are generated in the presence of 2-(trimethylsilyl)furan, two regioisomeric cycloadducts are formed in a 1:2 ratio. However, regioselectivity can be installed by fitting one bulky trimethylsilyl group into sterically critical positions of each of the two reaction components. Thus 3-fluoro-6-trimethylsilyl-1,2-didehydrobenzene and 2-(trimethylsilyl)furan give one cycloadduct exclusively. In this way, the Diels-Alder reaction between suitably adorned arynes and similarly designed furans can open an entry to naphthalene derivatives that have unprecedented substituent patterns that qualify them as building blocks for pharmaceutical or agricultural research. The acid-catalyzed isomerization of model 1,4-epoxy-1,4-dihydronaphthalenes, the aryne/furan cycloadducts, exhibits unexpected effects on rates and regioselectivity. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.
