BINOL‐3,3'‐Dicarboxylic Acid: Resolution for the Key Intermediate of ( <i>S</i> )‐bepotastine

(S)-Bepotastine is a highly selective histamine H1-receptor antagonist in the treatment of allergic rhinitis and other allergic diseases. We achieved a facile and convenient synthesis of (S)-bepotastine by resolving an early stage synthetic precursor. We devised a new class of resolving agent, BINOL-3,3'-dicarboxylic acid which could be considered as an axial version of tartaric acid. As the first example, we successfully resolved racemic piperidinyl ether by (S)-BINOL-3,3'-dicarboxylic acid with high optical purity. The final installation is quite straightforward and readily accomplished without any chiral loss.