ISSN:
0899-0042
Keywords:
enantioselectivity
;
mixed-ligand copper complexes
;
formation constants
;
amino acids
;
1,3-dicarbonyl compounds
;
circular dichroism
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Circular dichroism (CD) spectra of individual mixed-ligand copper(II) complexes of 1,3-dicarbonyl compounds, (1S)- or (1R)-3-hydroxymethylene camphor, (1S)-3-trifluoroacetyl camphor, or (1R)-2-hydroxymethylene menthone, and α-amino acids, alanine, valine, proline, or their N-alkyl derivatives, were calculated from CD spectra of equilibrium solutions containing the above constituents in methanol or ethylene dichloride. Diastereomeric mixed-ligand complexes incorporating identical dicarbonyl but enantiomeric N-alkyl-α-amino acid ligands exhibit quasi-enantiomeric CD spectra. Unsubstituted amino acids, on the contrary, will make no decisive contributions to the net optical activity spectrum of the mixed-ligand complexes. Formation constants of diastereomeric mixed-ligand complexes have been calculated from data on disproportionation of the latter into corresponding equally paired complexes. Enantioselectivity was demonstrated to amount to up to 700 cal/mol. Possible steric structures of mixed-ligand complexes are discussed. © 1993 Wiley-Liss, Inc.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/chir.530050505
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