Dendritic polyols based on carbosilanes - lipophilic dendrimers with hydrophilic skin

Carbosilane dendrimers with up to 108 end groups were prepared by a divergent synthetic route via repeated alternating Grignard-reaction with allylmagnesium bromide and hydrosilylation. Quantitative hydroboration of the dendrimers was achieved with 9-BBN/H₂O₂,OH⁻. Employing this synthetic route, rather monodisperse dendritic polyols with lipophilic carbosilane core and hydrophilic shell were prepared. All dendrimers were characterized with MALDI-TOF, showing low polydispersities. The novel dendritic polyols constitute interesting molecular scaffolds for the preparation of unusual supermolecules. As an example, reaction with cholesteryl chloro-formiate was used to prepare a series of dendrimers with 12, 36 and 108 mesogenic cholesteryl end groups.