779284-19-4Relevant academic research and scientific papers
Asymmetric Michael addition organocatalyzed by α,β-dipeptides under solvent-free reaction conditions
Avila-Ortiz, C. Gabriela,Lenin, Diaz-Corona,Erika, Jiménez-González,Juaristi, Eusebio
, (2017/09/01)
The application of six novel α,β-dipeptides as chiral organocatalysts in the asymmetric Michael addition reaction between enolizable aldehydes and N-arylmaleimides or nitroolefins is described. With N-arylmaleimides as substrates, the best results were achieved with dipeptide 2 as a catalyst in the presence of aq. NaOH. Whereas dipeptides 4 and 6 in conjunction with 4-dimethylaminopyridine (DMAP) and thiourea as a hydrogen bond donor proved to be highly efficient organocatalytic systems in the enantioselective reaction between isobutyraldehyde and various nitroolefins.
Solution-phase synthesis of novel seven-membered cyclic dipeptides containing α- And β-amino acids
Jimenez-Gonzalez, Erika,Gabriela Avila-Ortiz, C.,Gonzalez-Olvera, Rodrigo,Vargas-Caporali, Jorge,Juaristi, Eusebio,Dewynter, Georges
, p. 9842 - 9852,11 (2020/08/20)
A convenient synthetic procedure for the preparation of seven-membered cyclic α,β-dipeptides is described. Following coupling of N-protected α-amino acids with N-substituted β-amino acid tert-butyl esters, that affords linear α,β-dipeptides, the protecting groups at the terminal functionalities were removed and the open-chain dipeptides were cyclized with phenylphosphonic dichloride, PhP(O)Cl2, to give the desired cyclic α,β-dipeptides in good yields. NMR studies, X-ray diffraction analysis, and DFT calculations provided evidence for the conformation adopted by these cyclic dipeptides in solution, in the solid-state, and in the gas phase.
