نتایج جستجو برای: chiral pyrrolidines
تعداد نتایج: 37647 فیلتر نتایج به سال:
The reaction between 3-methyl-4-nitro-5-styrylisoxazoles and ethyl isocyanoacetate proceeded under phase transfer catalysis to give enantioenriched monoadducts in high enantiomeric excess (up to 99% ee). The resulting adducts were subsequently cyclised to give 2,3-dihydropyrroles and substituted pyrrolidines in identical high ees and as a single diastereoisomer.
A simple and efficient protocol for the construction of substituted piperazines, piperidines, thiomorpholines, decahydroquinolines, perhydrocyclopenta[b]pyridine, and pyrrolidines bearing N-hydroxy substituents through intramolecular reductive cyclization of diketoximes using sodium cyanoborohydride is described.
Tetrasubstituted pyrrolidines representing analogs of homoproline were synthesized by three-component condensation of aryl(heteroaryl)aldehydes, asparagine and N-methylmaleimide (NMM). Compounds with (1S*, 3R*, 3aS*, 6aR*)-configuration at the corresponding carbon positions of the bicyclic pyrrolidine ring could be isolated ona preparative scale.
A hexafullereno-diporphyrinoid was obtained in a sequence of cycloaddition steps using porphyrins programmed for [4+2]-cycloaddition reactions and C(60)-fullerene.
In this article the utility of phosphoramidite ligands in enantioselective Au(I) catalysis was explored in the development of highly diastereo- and enantioselective Au(I)-catalyzed cycloadditions of allenenes. A Au(I)-catalyzed synthesis of 3,4-disubstituted pyrrolidines and γ-lactams is described. This reaction proceeds through the enantioselective Au(I)-catalyzed cyclization of allenenes to f...
carbon nanotubes (cnts) are specific structures with valuable characteristics. in general, the structure of each nanotube is defined by a unique chiral vector. in this paper, different structures of short single-walled cnts are simulated and their mechanical properties are determined using finite element method. for this aim, a simple algorithm is presented which is able to model the geometry o...
One of the problems encountered in CE separations of basic compounds is the adsorption of analytes onto the negatively charged capillary wall which could lead to poor repeatability of migration time and peak area. Additionally, separation of enantiomers of chiral of basic drugs is commonly carried out in low pH buffer which contributes to strong ionic interaction of the cationic drug ions with ...
An important property of electromagnetic fields, which arises from the interaction between fields and chiral molecules, is called optical chirality. By enhancing this field property, while maintaining constant input power, we are able to increase absorption of circularly polarized light by chiral molecules of a certain handedness. This enhancement is achieved through the use of achiral plasmoni...
Asymmetric coupling proceeds efficiently between propargylic acetates, cycloalkenes and electron-rich heteroarenes including indoles, pyrroles, activated furans thiophenes. 2,3-Disubstituted tetrahydrofurans pyrrolidines are produced in trans configuration excellent enantiomeric ratios. The reaction via Wacker-type attack of nucleophilic on alkenes by allenyl PdII species.
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