Chemical Modification of Polystyrene Resins. Approaches to the Binding of Reactive Functionalities to Polystyrene Resins through a Dimethylene Spacer

By an appropriate sequence of simple and often quantitative chemical steps, reticulated bromopolystyrene or (chloromethyl)polystyrene can be modified to support any of hydroxy, halo, acyloxy, sulfonoxy, amino, sulfonamido, thio, phosphino, or other chemical groups on a two-carbon spacer extending from the insoluble matrix. This structural feature can enhance stability, reactivity, and/or selectivity in many applications of functionalized polystyrenes as reagents or catalysts. For example, p-lithiated polystyrene reacts with ethylene oxide to afford p-(2-hydroxyethyl)polystyrene free from grafted oligoethylene glycol. (2-Hydroxyethyl)polystyrene is tosylated rapidly and quantitatively by treatment with diisopropylamine and tosyl chloride in refluxing carbon tetrachloride while a similar reaction of the supported alcohol with tosyl chloride in a tertiary amine leads directly and quantitatively to the quaternary ammonium salt resin. Other simple procedures have been devised to transform the tosylated polymer into primary, secondary, or tertiary amines without overalkylation.