نتایج جستجو برای: regio and chemoselective
تعداد نتایج: 16827812 فیلتر نتایج به سال:
Catalytic chemoselective reactions of innately less reactive functionalities over more are described. A cooperative catalyst comprising a soft Lewis acid/hard Brønsted base enabled activation hydroxyl group an amino group, allowing for nucleophilic addition to electron-deficient olefins. The reaction could be applicable variety alcohols, including pharmaceuticals, without requiring tedious prot...
efficient and chemoselective protection of aldehydes to the corresponding dimethyl acetals have been carried out by mixture of trimethyl orthoformate and methanol in the presence of a catalytic amount of tmscl or alcl3 under microwave irradiation. under these conditions, acetalization of ketones does not take place and they remain intact under reaction conditions. the results are compared with ...
Intermolecular photocatalytic hydroaminoalkylation (HAA) of alkenes have emerged as a powerful method for the construction alkyl amines. Although there are some studies aiming at stereoselective HAA reactions, limited to electrophilic alkenes. Herein, we report highly regio-, diastereo-, and enantioselective electron-rich dienol ethers ?-amino radicals derived from acids using unified photoredo...
An efficient, 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,wit...
Chemoselective hydrogenation of 5-(hydroxymethyl)furfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) has been efficiently performed using bimetallic CuFe nanoparticles covered by thin carbon layers as catalysts.
Selective transformations of limonene by asco- and basidiomycetes were investigated. On the shake flask scale, Penicillium citrinum hydrated R-(+)-limonene to a-terpineol [83% regioselectivity (rs), more than 80 mg l(-1) product yield], and Gongronella butleri catalysed the terminal oxidation to yield perillyl alcohol (60% rs, 16 mg l(-1)). On the laboratory bioreactor scale, Penicillium digita...
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