An efficient asymmetric synthesis of the potent β-blocker ICI-118,551 allows the determination of enantiomer dependency on biological activity

A highly efficient, practical and flexible two-step asymmetric synthesis of the β2-selective β-blocker ICI 118,551 is reported, allowing an unambiguous determination of the dependency of biological activity with optical activity, revealing the S,S-enantiomer to be the most potent.