Periphery modified heterogeneous hyperbranched polyether as catalyst and support for organic synthesis

Abstract

In recent years, solid supported organic synthetic methodology has newlineevolved as an inevitable part of heterogeneous organocatalyst design and newlinecombinatorial chemistry involving multistep organic transformations. newlineConsidering the immense advantages of solid phase methodology over the newlinesolution phase synthesis, a lot of polymeric supports were introduced with newlinevarying properties. Fine tuning of the properties of the solid support is newlinestill going on to meet the specific requirements of an efficient support newlinematerial. The main drawbacks of the classical crosslinked resins are the newlinelimited loading capacity and the poor swelling capacity in a desired newlinesolvent system. In recent years, multifunctional branched architectures newlinehave emerged as promising support materials for catalysts. Dendrimers newlinewere used widely for a long period. Now, increased attention is given to newlinethe irregular counterpart, hyperbranched polymers mainly due to the ease newlineof synthesis and the structural similarity to dendrimers. The compact newlinestructure, high density of functional groups, three-dimensional globular newlineshape etc. are the other interesting features of hyperbranched polymers. newlineAlso, hyperbranched polymers show higher flexibility than the dendritic newlinestructure, which is one of the desired qualities for a novel support newlinecarrying catalytically active material. The practical application of newlinehyperbranched polymers as support materials for catalyst or reagent is newlinestill limited due to the difficulty in separation from the reaction mixture newlineand recycling. Grafting of hyperbranched polymer to the resin is a newlineversatile method for the introduction of a large number of functional newlinegroups to the solid support within one step. Also, due to grafting, swelling newlineproperty of the solid support can be modified. Heterogeneous newlinehyperbranched architectures (hyperbranched solid support) mimic the newlinedendronized resin in properties and they can be easily synthesized in large newlinequantities within one step.