Synthesis of polyhydroxylated pyrrolizidine and indolizidine compounds and their glycosidase inhibitory activities

The synthesis of the natural product 3-epi-casuarine and two tricyclic ether bridged analogues, plus 7-deoxy-3,6-diepi-casuarine, 7-epi-australine, 1-epi-castanospermine and 1,6-diepi-castanospermine is described. The glycosidase inhibitory activities of these compounds, along with that of uniflorine A and other polyhydroxylated pyrrolizidines and indolizidines that we have published before, are reported.