- Modular Synthesis of α-Substituted Alkenyl Acetals by a Palladium-Catalyzed Suzuki Reaction of α-Haloalkenyl Acetals with Organoboranes
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A modular and straightforward synthetic strategy for the preparation of α-substituted alkenyl acetals has been developed. α-Haloalkenyl acetals react smoothly with (het)aryl boronic acids, aryl boronates, or B-Alkyl-9-borabicyclo[3.3.1]nonanes through Pd-catalyzed Suzuki cross-coupling under mild conditions with good to high yields. This protocol features a broad substrate scope and good functional-group compatibility, and is easily scaled up.
- Zhang, Li
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p. 723 - 727
(2021/02/26)
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- Cascade annulative π-extension for the rapid construction of carbazole based polyaromatic hydrocarbons
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A Br?nsted acid catalyzed cascade benzannulation strategy for the one-pot synthesis of densely populated poly-aryl benzo[a]carbazole architectures is disclosed from easily affordable fundamental commodities. The efficacy of this technique was further validated via the concise synthesis of structurally unique carbazole based poly-aromatic hydrocarbons. Furthermore, the photo-physical properties of the synthesized compounds are thoroughly investigated.
- Banerjee, Ankush,Ghosh, Meghna,Kundu, Samrat,Maji, Modhu Sudan,Pal, Shyam Chand
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p. 5762 - 5765
(2021/06/16)
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- Synergistic Catalysis of Se and Cu for the Activation of α-H of Methyl Ketones with Molecular Oxygen/Alcohol to Produce α-Keto Acetals?
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Selenium and copper synergistically catalyzed the oxidation/alkoxylation of methyl ketones to synthesize α-keto acetals directly. Using O2 as oxidant and alcohol as solvent and alkoxylation reagent, the reaction is practical from industrial viewpoint. Mechanistic studies revealed that copper promoted the oxidation of organoselenium intermediates with O2 to allow the key rearrangement and selenoxide syn-elimination regenerating the catalytically active organoselenium species.
- Chen, Chao,Cao, Zhicheng,Zhang, Xu,Li, Yiming,Yu, Lei,Jiang, Xuefeng
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p. 1045 - 1051
(2020/06/30)
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- Tropylium salts as efficient organic Lewis acid catalysts for acetalization and transacetalization reactions in batch and flow
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Acetalization reactions play significant roles in the synthetically important masking chemistry of carbonyl compounds. Herein we demonstrate for the first time that tropylium salts can act as organic Lewis acid catalysts to facilitate acetalization and transacetalization reactions of a wide range of aldehyde substrates. This metal-free method works efficiently in both batch and flow conditions, prompting further future applications of tropylium organocatalysts in green synthesis.
- Lyons,Crocker,Enders,Nguyen
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supporting information
p. 3993 - 3996
(2017/09/08)
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- Cu(ii)-catalyzed esterification reaction via aerobic oxidative cleavage of C(CO)-C(alkyl) bonds
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A novel Cu(ii)-catalyzed aerobic oxidative esterification of simple ketones for the synthesis of esters has been developed with wide functional group tolerance. This process is assumed to go through a tandem sequence consisting of α-oxygenation/esterification/nucleophilic addition/C-C bond cleavage and carbon dioxide is released as the only byproduct.
- Ma, Ran,He, Liang-Nian,Liu, An-Hua,Song, Qing-Wen
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supporting information
p. 2145 - 2148
(2016/02/09)
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- Stereoselective Ketone Rearrangements with Hypervalent Iodine Reagents
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The first stereoselective version of an iodine(III)-mediated rearrangement of arylketones in the presence of orthoesters is described. The reaction products, α-arylated esters, are very useful intermediates in the synthesis of bioactive compounds such as ibuprofen. With chiral lactic acid-based iodine(III) reagents product selectivities of up to 73 % ee have been achieved.
- Malmedy, Florence,Wirth, Thomas
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supporting information
p. 16072 - 16077
(2016/10/30)
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- Cu-catalyzed aerobic oxygenation of 2-phenoxyacetophenones to alkyloxy acetophenones
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Cu-catalyzed aerobic oxygenation of 2-phenoxyacetophenones in the presence of alcohols was reported, and the corresponding alkyl benzoates, alkyloxy acetophenones and phenols were produced in high yields.
- Liu, Xinwei,Xu, Huanjun,Ma, Zhishuang,Zhang, Hongye,Wu, Cailing,Liu, Zhimin
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p. 27126 - 27129
(2016/03/25)
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- One-pot synthesis of α-ketoacetals from aryl methyl ketones in the presence of selenous acid catalyzed by boron trifluoride etherate
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A simple and efficient one-pot preparation of α-ketoacetals from substituted acetophenones and triethylorthoformate in the presence of H2SeO3 and BF3·Et2O as catalyst has been developed. The desired products are obtained in good yields by a simple protocol involving neat and mild reaction conditions. The present methodology provides an attractive alternative method for the preparation of α-ketoacetal derivatives.
- Kharkongor, Icydora,Myrboh, Bekington
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p. 4359 - 4362
(2015/06/22)
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- [1,2,4]TRIAZOLO[4,3-B][1,2,4]TRIAZINE COMPOUND, PREPARATION METHOD AND USE THEREOF
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The present invention relates to a structurally novel [1,2,4]triazolo[4,3-b][1,2,4]triazine compounds represented by formula (I) or formula (II), pharmaceutically acceptable salts thereof, prodrugs thereof, hydrates or solvates thereof, and also relates to a preparation method of the compounds, a pharmaceutical composition comprising a therapeutically effective amount of the compounds, as well as the use thereof as protein tyrosine kinase inhibitors, particularly as c-Met inhibitors, in the preparation of medicaments for the prevention and/or treatment of diseases associated with c-Met abnormality.
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- Enantioselective cyanosilylation of α,α-dialkoxy ketones catalyzed by proline-derived in-situ-prepared N-oxide as bifunctional organocatalyst
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Bifunctional N,N′-dioxide catalysts have been developed for highly enantioselective cyanosilylation of α,α-dialkoxy ketones. This process, catalyzed by in-situ-prepared proline-derived N,N′-dioxide 2b, produced the corresponding cyanohydrin trimethylsilyl ethers in excellent yields (up to 99%) with high enantioselectivities (up to 93% ee). A reasonable mechanism was proposed according to the observation of the linear effect, 1H NMR spectra, isolated cyanohydrin, and the roles of the NH and N-oxide moieties of the catalyst.
- Qin, Bo,Liu, Xiaohua,Shi, Jian,Zheng, Ke,Zhao, Haitao,Feng, Xiaoming
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p. 2374 - 2378
(2007/10/03)
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- Lithographic printing method
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A lithographic printing plate precursor comprising a support and an image-recording layer containing at least one infrared absorbing agent of a cyanine dye in which a HOMO energy level of each of substituents present on both terminal nitrogen atoms is -10.0 eV or higher. An infrared absorbing agent of a cyanide dye represented by formula (V) shown below: wherein Z 1 and Z 2 each independently represents an aromatic ring which may have a substituent or a hetero aromatic ring which may have a substituent; R 10 and R 20 each independently represents a phenyl group, a naphtyl group, an anthracenyl group, a carbazolyl group or a phenothiazinyl group each of which may have a substituent; A - represents an anion which exists in case of being necessary for neutralizing a charge and is selected from a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion and a sulfonate ion; and n represents 1 or 2.
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- Fluorination of 2-oxo-ethane derivatives with diethylaminosulfur trifluoride (DAST)
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The fluorination of 2-oxo-ethane derivatives with DAST is described. The use of Znl2 as a catalyst improves the yield in the fluorination of 2-phenyl-2-oxo-acetonitrile with DAST.
- Haegele, Gerhard,Haas, Andreas
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- Liquid photoinitiator mixtures
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Liquid highly active photoinitiators are obtained by dissolving a solid photoinitiator of the titanocene type in liquid photoinitiators of the acetal or ketal type. The liquid mixtures have a long dark storage stability.
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- Diethoxymethyllithium: generation via transmetallation of diethoxymethyltributyltin, stability, nucleophilic reactivity in addition reactions, and use as a precursor of group 14 formylmetals
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Diethoxymethyltributyltin and bimethoxymethyltributyltin have been converted into the corresponding dialkoxymethyllithium reagents upon transmetallation by n-butyllithium in THF.Temperature appears to be the key parameter controlling the decomposition of diethoxy- (or dimethoxy-) methyllithium.Inside the reactor, -78 deg C appears to be the borderline temperature to allow trapping experiments with electrophiles before decomposition.Nucleophilic addition on carbonyl derivatives has been examined and the evaluation of stereochemical trends and regiochemical trends (1,2-/1,4-addition in the case of α,β-enones) has been used to characterize the chemical behavior of this type of reagent.Furthermore, in the case of electrophilic trapping by chlorosilanes or chlorogermanes, the expected α-silyl or α-germylacetals have been obtained and their hydrolysis into group 14 formylmetals has been observed using electronic spectrometry.Keywords: transmetallation / formylanion equivalent / d1 umpoled reagent / diethoxymethyllithium / nucleophilic reactivity / formylsilanes / formylgermanes / formylstannanes
- Parrain, Jean-Luc,Beaudet, Isabelle,Cintrat, Jean-Christophe,Duchene, Alain,Quintard, Jean-Paul
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p. 304 - 312
(2007/10/02)
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- Oxygen-containing titanocenes, and the use thereof
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Titanocenes of the formula I STR1 in which R1 are cyclopentadienyl? groups and R2 and R3 are aromatic radicals which are substituted in both ortho-positions by fluorine and, in addition, are substituted by an acyloxy group are suitable as photoinitiators for the photopolymerization of ethylenically unsaturated compounds.
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- Titanocenes, the use thereof, and N-substituted pyrroles
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Titanocenes containing two 5-membered cyclodienyl groups, for example cyclopentadienyl, and one or two 6-membered carbocyclic or 5- or 6-membered heterocyclic aromatic rings which are substituted by a fluorine atom in at least one of the two ortho-positions to the titanium-carbon bond and contain, as a further substituent, unsubstituted or substituted 1-pyrryl, are suitable as photoinitiators for radiation-induced polymerization of ethylenically unsaturated compounds.
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- Titanocenes, the use thereof, and n-substituted fluoroanilines
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Titanocenes containing two 5-membered cyclodienyl gropus, for example cyclopentadienyl, and one or two 6-membered carbocyclic or 5- or 6-membered heterocyclic aromatic rings which are substituted by a fluorine atom in at least one of the two ortho-positions to the titanium-carbon bond and contain, as further substituents, a substituted amino radical, are suitable as photoinitiators for radiation-induced polymerization of ethylenically unsaturated compounds.
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- Novel nitrogen-containing titanocenes, and the use thereof
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Titanocenes of the formula I STR1 in which R1 are cyclopentadienyl? groups and R2 and R3 are aromatic radicals which are substituted in both ortho-positions by fluorine and, in addition, are substituted by a pyrrylalkyl group, amidoalkyl group or imidoalkyl group, are suitable as photoinitiators for the photopolymerization of ethylenically unsaturated compounds.
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- Selenium-Mediated Conversion of Alkynes into α-Dicarbonyl Compounds
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The reaction of terminal and internal alkynes with diphenyl diselenide and ammonium peroxydisulfate in methanol proceeds smoothly to give α-keto acetals and α-keto ketals, respectively.This one-pot procedure is suggested to proceed through the initial formation of phenylselenenyl sulfate, a strong electrophilic reagent which effects the methoxyselenenylation of the alkynes.The addition products thus formed suffer methoxydeselenenylation giving the observed products and regenerating the phenylselenenylating agent.In some cases the reaction can be carried out using only catalytic amounts of diphenyl diselenide.The same reaction carried out in the presence of water or of ethylene glycol gives the unprotected or the diprotected α-dicarbonyl compounds, respectively.
- Tiecco, Marcello,Testaferri, Lorenzo,Tingoli, Marco,Chianelli, Donatella,Bartoli, Donatella
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p. 4529 - 4534
(2007/10/02)
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