19943-16-9Relevant articles and documents
The Preparation and Resolution of Novel Axially Chiral Pyrazine-Containing P,N Ligands for Asymmetric Catalysis and Their Application in Palladium-Catalysed Allylic Substitution
Goddard, Richard,Guiry, Patrick J.,Kelly, Sarah
, (2022/01/04)
The design and synthesis of two novel pyrazine-containing ligands, 3,6-diisopropyl-Pyrazinap and Np?Cy-Pyrazinap, has been described. Their synthesis was accomplished in six and nine steps, respectively, in which the key steps were the formation of the biaryl linkage through a Suzuki cross-coupling reaction and the formation of the aryl to phosphorus bond employing nickel catalysis. Both ligands were resolved through the formation of diastereomeric palladacycles and in the case of the isolated diastereomer formed from 3,6-diisopropyl-Pyrazinap, an X-ray crystal structure showed the axial chirality to possess (S)-configuration. The two enantiopure ligands were applied to the palladium-catalysed allylic alkylation of 1,3-diphenylprop-2-enyl acetate with dimethyl malonate and afforded conversions of up to 100 % and 99 % with enantioselectivities of up to 92 % ee and 78 % ee, respectively. A series of 1,1,3-triphenylallyl and 1,3-diphenylallyl palladium complexes were prepared and their solution structures and dynamic behaviour elucidated by 2D-COSY and NOESY NMR spectroscopic experiments.
Interfacial supramolecular biomimetic epoxidation catalysed by cyclic dipeptides
Bérubé, Christopher,Barbeau, Xavier,Cardinal, Sébastien,Boudreault, Pierre-Luc,Bouchard, Corinne,Delcey, Nicolas,Lagüe, Patrick,Voyer, Normand
, p. 330 - 349 (2017/03/15)
We synthesised a library of cis- and trans-cyclic dipeptides and evaluated their efficacy as catalysts in the asymmetric Weitz-Scheffer epoxidation of trans-chalcone. A thorough investigation relying on structure-activity studies and computational studies provided insights into the mechanism of the process. Our results revealed some structural features required for efficient conversion and for introduction of chirality into the product. The cyclic dipeptide acts as a catalyst by templating a supramolecular arrangement at the aqueous-organic interface required for efficient transformations to occur. Among all cyclic dipeptides investigated, cyclo(Leu-Leu) was the most efficient supramolecular catalyst.
Linear and cyclic dipeptides with antimalarial activity
Perez-Picaso, Lemuel,Rios, Maria Yolanda,Olivo, Horacio F.,Argotte-Ramos, Rocio,Rodriguez-Gutierrez, Maria
, p. 7048 - 7051,4 (2012/12/12)
Several natural and synthetic polypeptides possess important antimalarial activity. Shorter peptides with potent antimalarial activity have also been described, among them linear di-, tri-, tetra- and pentapeptides and their cyclic analogs. In an attempt
