نتایج جستجو برای: ketoesters
تعداد نتایج: 289 فیلتر نتایج به سال:
The synthesis of spirocyclic amide acetals (33–93 %) has been achieved through Ru(II)-catalyzed condensations N-carbamate protected pyrrolidinones with metal carbenes derived from α-diazo-β-ketoesters. Thanks to the mildness diazo decomposition conditions induced by a 1 : combination [CpRu(MeCN)3][BArF] and 1,10-phenanthroline, formation sensitive products is possible. Full characterization thi...
In this research, a Brønsted acidic ionic liquid namely N1,N1,N2,N2-tetramethyl-N1,N2-bis(sulfo)ethane-1,2-diaminium chloride {[TMBSED][Cl]2} was employed as a highly efficient catalyst for the solvent-free production of some nitrogen- and oxygen-containing heterocyclic compounds including: (i) polyhydroquinolines (from arylaldehydes, dimedone, β-ketoesters and ammonium acetate), (ii) 3,4-dihyd...
A variety of chiral N-phosphinyl α-imino esters have been synthesized for the first time from ketoesters and phosphinylamide, which were then reduced by L-selectride to give the corresponding N-phosphinyl-protected α-amino esters. The reduction proceeded very well with excellent chemical yields (88-98%) as well as high diastereoselectivities (96:4 to 99:1). Some of these products could be obtai...
This communication describes the first proof of concept for an asymmetric α-cyanation of β-ketoesters using a hypervalent iodine-based electrophilic cyanide-transfer reagent. A series of different organocatalysts has been investigated and it was found that the use of naturally occurring Cinchona alkaloids allows obtaining the target products in good yields and with moderate enantioselectivities...
The first enantioselective copper-catalyzed decarboxylative propargylic alkylation has been developed. Treatment of propargyl β-ketoesters with a catalyst, prepared in situ from [Cu(CH3 CN)4 BF4 ] and a newly developed chiral tridentate ketimine P,N,N-ligand under mild reaction conditions, generates β-ethynyl ketones in good yields and with high enantioselectivities without requiring the pregen...
benzylaminoalkenones and benzylaminoalkenoates 3 were synthesized from reaction of benzylamine with corresponding 1,3-diketones and 1,3-ketoesters in the presence of catalytic amount of chloroacetic acid under microwave radiation. this method offers several advantages including high yield of products, recyclable of the catalyst and easy experimental work-up procedure.
N-Substituted α-amino esters are widely used as chiral intermediates in a range of pharmaceuticals. Here we report the enantioselective biocatalyic synthesis N-substituted through direct reductive coupling α-ketoesters and amines employing sequence diverse metagenomic imine reductases (IREDs). Both enantiomers were obtained with high conversion excellent enantioselectivity under mild reaction c...
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