Abstract The Pd‐catalyzed coupling of aryl/alkenyl halides and triflates with reagent (II) allows an efficient access to a number of trichlorophenyl esters.
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Dehydrative esterification of carboxylic acids with alcohols in water was efficiently catalyzed by hydrophobic polystyrene-supported sulfonic acids as recoverable and reusable catalysts. In these reactions, esters were obtained in high yields without using any dehydrating agents or apparatus. The sulfonic acid contents of the catalysts and the presence of long alkyl chains on the benzene rings of polystyrene significantly affected the catalytic activity.
An agarose gel upon which a water-soluble cyclophane having three quaternary nitrogens was immobilized, Gel-QCP (3), was synthesized and its properties as a chromatographic stationary phase were studied. The affinity of Gel-QCP for several neutral and anionic aromatic guests was broadly consistent with that of the parent cyclophane (2). This suggests that the guest separation is attributable to the formation of inclusion complexes between the cyclophane moiety of Gel-QCP and the guests. Non-specific electrostatic interaction also influences anionic guests, but this effect is reduced by using an aqueous solution of NaCl as an eluent.
Allylation reactions of various benzoylhydrazones with tetraallyltin were found to proceed smoothly in the presence of scandium triflate as a Lewis acid catalyst at ambient temperature in aqueous media, to afford the corresponding homoallylic amine derivatives in high yields. Three-component reactions of aldehydes, benzoylhydrazine, and tetraallyltin were also catalyzed by scandium triflate in the same media. Furthermore, a simple procedure to prepare oxazolidinone derivatives utilizing these reactions was developed.
Fluorobenzenes with directing groups such as hydroxy, hydroxymethyl, and amino underwent ortho-selective cross-coupling with Grignard reagents in the presence of palladium-based catalysts, with dichlorobis(tricyclohexylphosphine)palladium [PdCl2(PCy3)2] found to be the optimum catalyst. Fluoro and chloro groups at positions other than ortho to the directing groups survived under the reaction conditions.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCatalytic Asymmetric Benzylation of Achiral Lithium Enolates Using a Chiral Ligand for Lithium in the Presence of an Achiral LigandMitsuko Imai, Atsushi Hagihara, Hisashi Kawasaki, Kei Manabe, and Kenji KogaCite this: J. Am. Chem. Soc. 1994, 116, 19, 8829–8830Publication Date (Print):September 1, 1994Publication History Published online1 May 2002Published inissue 1 September 1994https://pubs.acs.org/doi/10.1021/ja00098a061https://doi.org/10.1021/ja00098a061research-articleACS PublicationsRequest reuse permissionsArticle Views1611Altmetric-Citations112LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Abstract New types of Lewis acids as water-stable catalysts have been developed. Metal salts such as rare earth metal triflates can be used in carbon_carbon bond-forming reactions in aqueous media. These salts can be recovered after the reactions and reused. Furthermore, Lewis acid_surfactant-combined catalysts, which can be used for reactions in water without using any organic solvents, have been also developed. Finally, Lewis acid catalysis in supercritical carbon dioxide has been successfully performed. These investigations will contribute to development of environmentally friendly Lewis acid catalysis.
