Chemoenzymatic synthesis of azacycloalkan-3-ols

Optically active ω-bromocyanohydrins are easily synthesized through an enantioselective (R)-oxynitrilase-catalyzed reaction from their corresponding ω-bromoaldehydes. These cyanohydrins are starting materials for the preparation of medium size nitrogen heterocycles. The reduction of (R)-(+)-5-bromo-2-hydroxypentanenitrile affords, in one-pot, piperidin-3-ol. Azepan-3-ol and azocan-3-ol are readily obtained from their corresponding cyanohydrins in high enantiomeric excesses.