نتایج جستجو برای: regio and chemoselective
تعداد نتایج: 16827812 فیلتر نتایج به سال:
Magnetically separable gold-nanoparticle catalyst was prepared, and it showed excellent activity for chemoselective reduction of nitroarenes with hydrosilanes.
Nano-silica supported boron trifluoride (BF3.SiO2) is an efficient, reusable and eco-friendly catalyst for chemoselective thioacetalization of aldehydes and ketones. So, this catalyst was applied for transthioacetalization of acetals and acylals into their corresponding 1,3-dithiolanes or 1,3-dithianes in good to excellent yields. The reactions were carried out at room temperature under solven...
Nano-silica supported boron trifluoride (BF3.SiO2) is an efficient, reusable and eco-friendly catalyst for chemoselective thioacetalization of aldehydes and ketones. So, this catalyst was applied for transthioacetalization of acetals and acylals into their corresponding 1,3-dithiolanes or 1,3-dithianes in good to excellent yields. The reactions were carried out at room temperature under solven...
Chemoselective ligation, including "click" chemistry, has found wide utility in general synthetic strategies and the specific modification of polymers and biomolecules. This has resulted in a number of applications of such approaches, particularly in the biomedical area, including diagnostic imaging and drug delivery. However, tools to chemoselectively decorate target molecules with multiple co...
A regio- and stereoselective method has been developed for the synthesis of novel fluorinated 2-aminocyclohexanecarboxylic acid derivatives with the fluorine attached to position 4 of the ring. The synthesis starts from either cis- or trans-β-aminocyclohex-4-enecarboxylic acids and involves regio- and stereoselective transformation of the ring C-C double bond through iodooxazine formation and h...
The rhodium-catalyzed regio- and enantioselective amination of racemic tertiary allylic trichloroacetimidates with a variety of aniline nucleophiles is a direct and efficient route to chiral α,α-disubstituted allylic N-arylamines. We describe the first dynamic kinetic asymmetric transformations of racemic tertiary allylic electrophiles with anilines utilizing a chiral diene-ligated rhodium cata...
Poniendo el foco en las relaciones entre la Italia española y Cataluña, presente artículo ofrece un análisis comparativo de prácticas carreras episcopales patronato regio. En particular, se estudia formación circulación élites eclesiásticas seno red episcopal regio monarquía ibérica. La emblemática prestigiosa carrera desarrollada Cataluña por napolitano Benet Tocco evidencia rol que los eclesi...
Diaryliodonium salts are versatile arylating agents but generally feature poor atom economy. In this issue of Chem, Olofsson and co-workers describe a novel chemoselective SNAr reaction that sets up second in situ arylation incorporates the iodoarene component cascade with excellent The N- O-based functionalities, producing diarylamine ether structures essential to many biologically active mole...
the catalytic highly regio-, diastereo-, and enantioselective synthesis of a small library of spiropyrrolizidineoxindolesvia a four-component 1,3-dipolar cycloaddition reactionof azomethineylides, derived from isatin, with electron-deficient dipolarophilewas described. the process occurs at room temperature in aqueous ethanol as a green solvent and in the presence of a bidendatebis(imine)–cu(ii...
one-pot, four-component procedure for the synthesis of a small library of new chiral spiro- oxindolopyrrolidines with high regio-, diastereo- (>99:1 dr), and enantioselectivity (up to 80% ee) is described. in this process, the regio- and stereochemical 1,3-dipolar cycloaddition of azomethine ylides, which were generated insitu by the reaction of isatin derivatives and sarcosin,with optically ac...
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