Proline-Based Boronic Acid Receptors for Chiral Recognition of Glucose

Chiral
recognition remains a major challenge in the area of molecular
receptor design. With this research, we set out to explore the use
of proline-based receptors for chiral recognition. Importantly, the
proline structure allows for the introduction of at least two different
binding groups due to the availability of both an amine and carboxylic
acid group. Here we report a proof-of-concept exploration into the
chiral recognition of d/l-glucose as a model chiral
species, which prefers to bind to at least two boronic acid groups.
We evaluated several proline-based receptors incorporating two phenylboronic
acid groups, respectively, at the N- and C-termini of the amino acid
residue, via amide bonds. We confirmed that the receptors exhibited
chiral recognition using CD, 1H NMR, and 19F
NMR spectroscopy. Given the derivation diversity available, our strategy
to use proline-based receptors for chiral recognition holds significant
promise for extension to other chiral systems.