Transformation of linear oligoketosides into macrocyclic neoglycoconjugates

The macrocyclization of linear d-galacto-2-heptulopyranose-containing oligoketosides has been carried out by intramolecular glycosidation and ring-closing metathesis. The aglycon fragment of the cyclic neglycoconjugates thus formed was an alkylidene or a polyether chain. One of the oligoketoside–crown ethers showed a moderate asymmetric induction in the Cram model phenyl acetate–acrylate addition.