Multicomponent Approach to Homo- and Hetero-Multivalent Glycomimetics Bearing Rare Monosaccharides.

We applied a multicomponent approach to access a library of densely functionalized homo- and hetero-multivalent glycomimetics comprising aldehyde, amine, and isocyanide components related to isopropylidene-protected d-fructose, l-sorbose, d-galactose, and d-allose. Passerini products were obtained in very good yields (up to 78%) and high diastereoselectivities (up to 98:2). Three types of products were obtained by the Ugi reaction; along with the "classical" four-component product, α-acylaminoamides, a three-component α-aminoamides, and a four- component α-aminoacylamides were isolated. The presence of multiple pathways is rationalized by the structure of the imidate intermediate, mainly influenced by the amine component.