Reaction of N-acetyldehydrophenylalanyl-S-proline with Ca(II) and Ni(II) ions and its role in asymmetric hydrogenation
摘要:
N-Ac-DELTAPhe-S-Pro forms strong coordination complexes with the CO2H group of the proline residue and weak coordination complexes through the -C(= O)-N groups with Ca(II) and Ni(II) ions in 95% aqueous methanol as indicated by the pK(a) values, PMR spectroscopy, and paramagnetic broadening of the C-13 NMR signals in the nickel complex. Complex formation enhances the rigidity of the dehydrodipeptide conformation, leading to a strong increase in the optical yield upon hydrogenation over achiral catalysts.
Complexes of Ca2+ and Mg2+ withN-acetyl-α,β-dehydrodipeptides: the state in an alcoholic solution and its relationship with asymmetric induction upon diastereoselective hydrogenation
摘要:
In an alcoholic solution, N-acetyl-alpha,beta-dehydrodipeptides interact with Ca2+ and Mg2+ ions to form complex particles containing several dehydrodipeptide molecules per metal ion. The composition of these particles and steric interactions in them determine the acidity of the carboxyl groups and the degree of asymmetric induction upon diastereoselective hydrogenation.
Behrens; Doherty; Bergmann, Journal of Biological Chemistry, 1940, vol. 136, p. 61,64
作者:Behrens、Doherty、Bergmann
DOI:——
日期:——
Asymmetric hydrogenation ofN-acetyldehydrodipeptide complexes with Mg(II) and Ca(II) ions
作者:I. N. Lisichkina、A. I. Vinogradova、N. B. Sukhorukova、E. V. Tselyapina、M. B. Saporovskaya、V. M. Belikov
DOI:10.1007/bf00698456
日期:1993.3
N-Ac-DELTA-Phe-AA form labile complexes with Mg(II) ions. Potentiometric titration data show that the carboxyl group of the dehydrodipeptide in them scarcely participates in complexation, unlike the complexes with Ca(II) ions, The hydrogenation of these complexes over Pd/C occurs asymmetrically, the diastereomeric excess being as high as 58%.
Diastereoselective hydrogenation of N-acetyldehydrodipeptides
作者:V. K. Latov、A. I. Vinogradova、M. B. Saporovskaya、V. M. Belikov