Beschreibung:
<jats:title>Abstract</jats:title><jats:p>A novel straightforward chemoenzymatic procedure for the synthesis of hyacinthacine stereoisomers based on the aldol addition of dihydroxyacetone phosphate (DHAP) to <jats:italic>N</jats:italic>‐Cbz‐prolinal under catalysis by <jats:sc>L</jats:sc>‐rhamnulose 1‐phosphate aldolase from <jats:italic>E. coli</jats:italic> is presented. The synthesis is complemented by a simple and effective purification protocol consisting of ion‐exchange chromatography on CM‐sepharose. As examples, (−)‐hyacinthacine A<jats:sub>2</jats:sub> [the enantiomer of (+)‐hyacinthacine A<jats:sub>2</jats:sub>], 7‐deoxy‐2‐epialexine (the enantiomer of 3‐epihyacinthacine A<jats:sub>2</jats:sub>), <jats:italic>ent</jats:italic>‐7‐deoxyalexine (the enantiomer of 7‐deoxyalexine) and 2‐epihyacinthacine A<jats:sub>2</jats:sub> were synthesized by these procedures and characterized for the first time. These new isomers were assayed as inhibitors of glycosidases. As a result, (−)‐hyacinthacine A<jats:sub>2</jats:sub> demonstrated to be a good inhibitor of α‐<jats:sc>D</jats:sc>‐glucosidase from rice whereas the natural enantiomer, hyacinthacine A<jats:sub>2</jats:sub>, was not. Moreover, a new family of inhibitors of α‐<jats:sc>L</jats:sc>‐rhamnosidase was uncovered.</jats:p>