Résumé
Ready access to natural (-)-lentiginosine and its pyrrolizidinic analogue from a chiral vinylic epoxyamine in a straightforward five-step sequence is presented. Careful use of the RCM reaction on aminotriols and constitutes the key feature of the synthetic pathway. The alpha-amyloglucosidase inhibitory activities of the target compounds were evaluated and showed that the more easily accessible pyrrolizidinic analogue possesses an inhibitory activity quite similar to that of (-)-lentiginosine.