نتایج جستجو برای: chiral pyrrolidines
تعداد نتایج: 37647 فیلتر نتایج به سال:
Experimental determination of solubility and ternary phase diagram of chiral compound are of tedious and time consuming tasks, and in many cases, there is not enough experimental data for different enantiomeric compositions to access the experimental ternary phase diagram. Using thermodynamic models with predictive capability, having less dependency on experimental data, affords a great advanta...
route to vinyl epoxides and vinyl aziridines via chiral sulfur ylides, we were keen to develop their potential in synthesis further. It had been reported that palladium-catalyzed reactions of vinyl epoxides and aziridines with doubly activated Michael acceptors gave tetrahydrofurans and pyrrolidines in good yield but usually with poor stereocontrol. However, related reactions with singly activa...
Palladium-catalyzed aminoalkynylation of electronically unbiased olefins with iodoalkynes is reported. The picolinamide auxiliary enables for the first time syn-selective mono-, di- and trisubstituted alkenes to afford corresponding pyrrolidines in up 97 % yield as single diastereomers. Furthermore, through a C−H activation approach, allows rapid synthesis functionalized olefins, which are suit...
A very efficient route to the diastereoselective synthesis of polyhydroxy pyrrolidines, piperidines and azepanes from an aldehyde derivative of ribose is reported. Asymmetric α-amination of aldehydes using proline catalysed hydrazination is the key step in the synthesis. The method utilizes the stereocenters present in ribose and the extra carbon atoms present in the target molecules are incorp...
An organocatalytic strategy for the synthesis of tetrasubstituted pyrrolidines with monoactivated azomethine ylides in high enantiomeric excess and excellent exo/endo selectivity is presented. The key to success is the intramolecular activation via hydrogen bonding through an o-hydroxy group, which allows the dipolar cycloaddition to take place in the presence of azomethine ylides bearing only ...
N-Phenylsuccinimides and the corresponding pyrrolidines containing 9,10-dihydroanthracenyl skeletons were used for exploring their ability to coordinate RuCp(+) moieties through the aromatic rings. Electronic and steric tuning of ligands led to mono-, bi- and tri-metallic complexes. A full structural study was carried out in order to characterize the ruthenium organometallic compounds, proving ...
We have developed a general strategy for the synthesis of 2,5-syn disubstituted pyrrolidines that is based on the multi-faceted reactivity of the sulfone moiety and a 5-endo-trig cyclisation. This methodology was applied to the synthesis of indolizidine alkaloid monomorine I. Two factors were key to the success of this endeavour; the first was the choice of nitrogen protecting group whilst the ...
Homologation of readily available α-boryl pyrrolidines with metal carbenoids is especially challenging even when good leaving groups (Cl- ) are employed. By performing a solvent switch from Et2 O to CHCl3 , efficient 1,2-metalate rearrangement of the intermediate boronate occurs with both halide and ester leaving groups. The methodology was used in the total synthesis of the Stemona alkaloid (-...
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