Background::
α-phenylethanol and its derivatives are important intermediates for the
synthesis of a variety of chiral drugs.
Method::
The interaction mechanism of the two enantiomers of α-phenylethanol with β-CD was investigated
using 1H-NMR and ROESY. The loading of β-cyclodextrin (β-CD) as the host with the
chiral drug intermediate α-phenylethanol as the guest was investigated using high-resolution
NMR in D2O and quantum chemical calculations.
Results::
The results showed that both α-phenylethanol enantiomers were able to enter into the hydrophobic
cavity of β-CD and undergo enantiospecific interactions, while the combination of 2D
ROESY and quantum chemical calculations showed that the benzene ring of both R and S α-
phenylethanol was inserted into the β-CD cavity toward the small-port end. However, the most stable
poses of the two enantiomers were different, so the benzene ring of the S-enantiomer was oriented
more toward the small-port end of β-CD than that of the R-enantiomer, which was reflected
in the signals of 2D ROESY, which were obviously different.
Conclusion::
β-CD can enantioselectively recognize the α-phenylethanol enantiomers, and the 2D
ROESY method is a very direct and powerful tool in the recognition process of chiral host and
guest research.