Enantiodiscrimination of Inherently Chiral Thiacalixarenes by Residual Dipolar Couplings.
J Org Chem
; 2023 Jan 19.
Article
em En
| MEDLINE
| ID: mdl-36655948
ABSTRACT
Inherently chiral compounds, such as calixarenes, are chiral due to a nonplanar three-dimensional (3D) structure. Determining their conformation is essential to understand their properties, with nuclear magnetic resonance (NMR) spectroscopy being one applicable method. Using alignment media to measure residual dipolar couplings (RDCs) to obtain structural information is advantageous when classical NMR parameters like the nuclear Overhauser effect (NOE) or J-couplings fail. Besides providing more accurate structural information, the alignment media can induce different orientations ofâ¯enantiomers. In this study, we examined the ability of polyglutamates with different side-chain moietiesâpoly-γ-benzyl-l-glutamate (PBLG) and poly-γ-p-biphenylmethyl-l-glutamate (PBPMLG) âto enantiodifferentiate the inherently chiral phenoxathiin-based thiacalix[4]arenes. Both media, in combination with two solvents, allowed for enantiodiscrimination, which was, to the best of our knowledge, proved for the first time on inherently chiral compounds. Moreover, using the experimental RDCs, we investigated the calix[4]arenes conformational preferences in solution, quantitatively analyzed the differences in the alignment of the enantiomers, and discussed the pitfalls of the use of the RDC analysis.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
J Org Chem
Ano de publicação:
2023
Tipo de documento:
Article
País de afiliação:
República Tcheca