Synthesis and biological evaluation of the first example of an eight-membered iminoalditol

The synthesis of the first examples of eight-membered iminoalditols has been achieved from 2,3,4,6-tetra-O-benzyl-d-glucopyranose by way of a ring-closing metathesis. The (2R,3R,4R,5S)-2-hydroxymethyl-azocane-3,4,5-triol (3a), which has the d-gluco configuration for C-2–C-5 and appears to exist predominantly in a boat–chair conformation, is a weak inhibitor of glycosidases.