Starburst Polyether Dendrimers

Article abstract of DOI:10.1021/jo00233a002

The synthesis of two starburst polyether dendrimers, by a protection-deprotection scheme, is described.A bicyclic ortho ester or a dioxane is used to temporarily mask three or two hydroxyl groups, respectively.Dendrimer type I was synthesized with a pentaerythritol core and a hydroxymethyl bicyclic orthoformate as the dendrimer synthon, while in dendrimer type II, 1,1,1-tris(hydroxymethyl)ethane and a (hydroxymethyl)dioxane were used.Dendrimer type I is the most compact starburst molecule synthesized to date.No spacer groups or excess reagent are needed in the synthesis, even though all reactions occur at neopentyl positions.In just three generations, 108 functionalities are present in the exterior layer.The size of these molecules calculated from CPK models is in excellent agreement with the data obtained from size-exclusion chromatography.