An alternative route for the construction of carbosilane dendrimers uniformly functionalized with lactose or sialyllactose moieties

A new approach for the formation of an acetylthio linkage on aglycon by mea ns of a radical addition of thioacetic acid into the C-C double bond of the aglycon was examined. An introduction of a carbohydrate moiety into carbos ilane dendrimers was demonstrated using a one-pot coupling reaction in MeOH -DMF in the presence of NaOMe via removal of an acetyl group of the acetylt hio linkage in the saccharide moieties, producing a thiolate anion and a nu cleophilic replacement of the thiolate to dendric alkyl bromide to form car bosilane dendrimers uniformly bearing lactose or sialyllactose moieties thr ough thioether linkages in high yields. (C) 2001 Elsevier Science Ltd. All rights reserved.