Optimizing Photochirogenic Performance by Solvent-Driven Conformational Fixation in Enantiodifferentiating Photoisomerization of (Z)-Cyclooctene Mediated by Sensitizing ß-Cyclodextrin Hosts.
J Org Chem
; 87(3): 1679-1688, 2022 02 04.
Article
em En
| MEDLINE
| ID: mdl-34743518
ABSTRACT
Catalytic enantiodifferentiating photoisomerization of cyclooctene (1Z) included and sensitized by regioisomeric 6-O-(o-, m-, and p-methoxybenzoyl)-ß-cyclodextrins (CDs) was performed under a variety of solvent conditions for higher enantioselectivities. The enantiomeric excess (ee) of chiral (E)-isomer (1E) produced was a critical function of all the internal and external factors examined, in particular, the sensitizer structure and the solvent conditions, to afford (R)-1E in record-high ee's of up to 67% upon sensitization with the meta-substituted ß-CD host in water and salt solutions but neither in 50% aqueous ethanol nor with the ortho- and para-substituted hosts. The mechanistic origin of the sudden ee enhancement achieved under the specific conditions is discussed on the basis of the circular dichroism spectral behaviors upon substrate inclusion and the compensatory enthalpy-entropy relationship of the activation parameters for the enantiodifferentiating photoisomerization.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Beta-Ciclodextrinas
Idioma:
En
Revista:
J Org Chem
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
China