Polymer-supported oligoethylene glycols as heterogeneous multifunctional catalysts for nucleophilic substitution

We investigated various structurally modified polystyrene-supported oligoethylene glycols (PSoligoEG) in order to find an optimized PSoligoEG by examining the dependence of their catalytic activity on the oligoethylene glycol chain length and the loading level of the oligoethylene glycol portion on the polystyrene support. From this, we found that the PSpentaEG with the highest pentaEG loading had the best catalytic efficacy among the various PSoligoEGs in nucleophilic substitutions. This PSpentaEG absorbed both polar aprotic solvents, such as DMSO, DMF, and acetonitrile, as well as protic media, such as tert-amyl alcohol and aqueous acetone, and swelled considerably. To expand the scope of the PSpentaEG as a heterogeneous catalyst for diverse nucleophilic displacement reactions, we carried out the thioacetoxylation, nitrilation, azidation, iodination, bromination, chlorination, and methoxylation using the corresponding alkali metal salts in the presence of PSpentaEG in various solvents; all the reactions proceeded smoothly, affording the corresponding products in high yields.