Soluble Polymer-supported Reagents

By replacing insoluble cross-linked resins with soluble polymer supports, the well-estabhshed reaction conditions of classical organic chemistry can be more readily apphed, while still fadhtating product purification. However, soluble supports suffer from the hmitation of low loading capacity. The recently introduced fluorous synthesis methodology overcomes many of the drawbacks of both the insoluble beads and the soluble polymers, but the high cost of perfluoroalkane solvents, hmitation in solvent selection, and the need for specialized reagents may hmit its apphcations. 

Soluble polymers that have been used in hquid-phase methodologies are listed in Fig. 5.1 [3, 7, 8, 34, 35]. Polyethylene glycol and non-cross-linked polystyrene are some of the most often used polymeric carriers for organic synthesis and have found frequent use in the preparation of soluble polymer-supported catalysts and reagents consequently, a brief discussion of these polymers is warranted. 

For the use of soluble polymers in synthesis, see Liquid-Phase Chemistry Recent Advances in Soluble Polymer-Supported Catalysts, Reagents, and Synthesis, P. Wentworth, Jr., K. D. Janda, Chem. Commun. 1999, 1917-1924 and references cited therein. 

Soluble polymer supports, like their insoluble counterparts, offer the advantage of ease of separation. After carrying out a chemical process, the polymer reagent, catalyst, or substrate can be isolated by adding a nonsolvent, for instance, by adding isopropanol for PEG supports. 

Wentworth, P, Janda, K D, Liquid phase chemistry recent advances in soluble polymer-supported catalysts, reagents and synthesis, Chem. Commun., 1917-1924, 1999. 

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