نتایج جستجو برای: β ketoesters
تعداد نتایج: 177597 فیلتر نتایج به سال:
N1,N1,N2,N2-tetramethyl-N1,N2-bis(sulfo)ethane-1,2-diaminium chloride ([TMBSED][Cl]2) was synthesized as an acidic ionic liquid and characterized using FT-IR, 1H and 13C NMR, mass spectroscopy, TG, DTG and DTA techniques. This ionic liquid was employed as efficient catalyst for the extremely facile and efficient synthesis of dihydropyrrol-2-ones and functionalized tetrahydropyridines. One-pot f...
α-Quaternary ketones are accessed through novel enantioselective alkylations of allyl and propargyl electrophiles by unstabilized prochiral enolate nucleophiles in the presence of palladium complexes with various phosphinooxazoline (PHOX) ligands. Excellent yields and high enantiomeric excesses are obtained from three classes of enolate precursor: enol carbonates, enol silanes, and racemic β-ke...
This study describes the combined experimental and computational elucidation of the mechanism and origins of stereoselectivities in the NHC-catalyzed dynamic kinetic resolution (DKR) of α-substituted-β-ketoesters. Density functional theory computations reveal that the NHC-catalyzed DKR proceeds by two mechanisms, depending on the stereochemistry around the forming bond: 1) a concerted, asynchro...
A mild and efficient method has been developed for the preparation of substituted coumarins from reaction of various phenols with different β-ketoesters via Pechmann condensation in the presence of Brønsted acidic ionic liquid (N-(4-sulfonic acid) butyl triethylammonium hydrogen sulfate) as an effective catalyst under solvent-free conditions. Different phenols reacted with ethyl acetoacetate to...
Reaction of 1,19-di-unsubstituted b-bilene salts with alpha-ketoesters gives isoporphyrins, and eventually porphyrins, by way of an a,c-biladiene salt intermediate.
Using a combination of commercially available mesofluidic flow equipment and tubes packed with immobilised reagents and scavengers, a new synthesis of alpha-ketoesters is reported.
An organocatalysed and chemoselective one-pot oxa-Michael-cyclocondensation reaction of N-BocNHOH to unsaturated α-ketoesters is reported which affords an original entry to enantioenriched 3-isoxazoline carboxylate derivatives as biorelevant heterocyclic frameworks.
The organocatalytic ring-opening of N-tosyl protected aziridines by beta-ketoesters under chiral PTC-conditions, leading to the formation of optically active aminoethyl functionalised compounds with up to 99% ee, has been developed.
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