| Abstract
| - A divergent approach to synthesize dendritic aliphatic polyester structures based on 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) is described. The key building block is the anhydride ofisopropylidene-2,2-bis(methoxy)propionic acid which is synthesized in high yields through self-dehydration,utilizing N,N‘-dicyclohexylcarbodiimide (DCC) as reagent. The high reactivity of the anhydride towardhydroxyl groups makes the divergent synthesis of dendrimers and dendrons viable. Dendritic growthoccurs in the presence of protecting groups sensitive toward hydrogenolysis, such as benzyl esters andethers. The acetonide-protecting group is easily removed under acidic conditions using DOWEX 50W-X2resin in methanol. Fourth-generation dendrons and dendrimers were successfully synthesized in highyields utilizing 1.3−1.5 equiv of anhydride per hydroxyl group. Common characteristics of the esterificationreaction were short reaction time, mild reaction conditions, easy monitoring by NMR analysis, and simpleworkup. This synthetic approach opens up the possibility to utilize orthogonal protecting groups ofacetonide-protected 2,2-bis(hydroxymethyl)propionic anhydride as a novel building block.
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