Hyperbranched Polymeric Supports in Organic Synthesis

Transformations on this support included the synthesis of aminoketones from supported chloroketones as weU as biarylaldehydes after Suzuki cross-couphng reactions of supported bromo-benzaldehydes [21]. This dendritic polyglycerol was 

Parquette et al. reported on a disaccharide synthesis on a hyperbranched polyester support (Boltorn hyperbranched polymer) (16) (Fig. 7.9) [44]. This polymer was obtained in a one-step synthesis and offers low cost, high-loading capacities (8.8 mmol OH-groups g ), and the intermediates were soluble in most aprotic solvents. 

Two different kinds of cleavage protocols were investigated. The first was a light induced photo-release reaction followed by a chromatographic work-up. Also, reaction monitoring was performed by MALDl/TOF/MS since the LASER cleaves the disaccharide from the support The second is a hydrolytic cleavage reaction under degradation of the polymeric support and subsequent aqueous extraction to yield the pure product The disaccharides (20) were obtained in yields of 27-76%. 

Both strategies are tainted with disadvantages the first contains a conventional chromatographical purification and therefore does not profit from the actual benefits of polymer supported synthesis the second makes use of aqueous extraction, which is only possible after degradation of the polymeric support. The latter step 

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