Naphthalimide‐Based Chiral Fluorescence Sensor Employing (S)‐BINOL Unit for Highly Enantioselective Recognition of α‐Amino Alcohols with Opposite Chiral Selectivity

A new naphthalimide‐based fluorescent probe [(S)‐1 and (S)‐2] employing (S)‐BINOL unit as a chiral responsive group has been designed and synthesized. Ligand (S)‐1 showed greater fluorescence enhancement towards (R)‐amino alcohol and the value of enantiomeric fluorescence difference (ef) ratio reached as high as 7.07 for phenylalaninol while (S)‐phenylalaninol did not show much enhancement in fluorescence, whereas ligand (S)‐2 showed ef value of 4.49 for phenylalaninol. The fluorescence enhancement can be attributed to imine formation and H‐bonding. Further, the R/S chiral selectivity of ligands (S)‐1 and (S)‐2 is opposite. The chiral discrimination ability of (S)‐1 and (S)‐2 was tested via fluorescence, NMR and CD spectral analysis. The results indicated that the sensor (S)‐1 was very promising for use as a fluorescent sensor in determining the enantiomeric composition of α‐amino alcohols. A new naphthalimide‐based fluorescent probe [(S)‐1 and (S)‐2] employing (S)‐BINOL unit as a chiral responsive group has been designed and synthesized. The fluorescence enhancement can be attributed to imine formation and H‐bonding. Further, the R/S chiral selectivity of ligands (S)‐1 and (S)‐2 is opposite. The chiral discrimination ability of (S)‐1 and (S)‐2 was tested via fluorescence, NMR and CD spectral analysis.