Application of kinetic resolution using HCS as chiral auxiliary: novel synthesis of beta-blockers (S)-betaxolol and (S)-metoprolol.

Optically pure (S)-betaxolol and (S)-metoprolol were prepared with an extremely facile and practical method using kinetic resolution of beta-amino alcohols employing HCS as chiral auxiliary. High enantiomeric purity (ee > 99%) was achieved and the synthetic strategy is amenable to industrial scale-up.
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