The spirocyclopropyl moiety as a methyl surrogate in the structure of l-fucosidase and l-rhamnosidase inhibitors

Nitrogen-in-the-ring analogues of L-fucose and L-rhamnose were prepared, which feature a spirocyclopropyl moiety in place of the methyl group of the natural sugar. The synthetic route involved a titanium-mediated aminocyclopropanation of a glycononitrile as the key step. Four new spirocyclopropyl iminosugar analogues were generated, which displayed some activity towards L-fucosidase and L-rhamnosidase