2016 Elsevier Ltd This Letter describes the use of alkene-terminated polyisobutylene (PIB) as a support for oxidizing agents. Two oxidizing agents, an ionically immobilized PIB-bound perruthenate oxidation catalyst and a PIB-bound 2-iodoxybenzoic acid (IBX) oxidizing reagent, were studied. A perruthenate catalyst ionically bound to PIB was prepared by binding the perruthenate anion to PIB that contained either a terminal tetraalkylammonium or an imidazolium salt. The PIB supported ammonium and imidazolium perruthenate were both selectively soluble in heptane and effective in the oxidation of alcohols. While these PIB-bound perruthenate catalysts could be readily separated from products, recycling was less successful. A PIB bound 2-iodoxybenzoic (IBX) oxidizing agent was coupled to a PIB support with an ester bond. It was highly soluble in nonpolar and moderately polar organic solvents. By taking advantage of PIB's heptane solubility, the spent IBX reagent could be easily separated from products by a liquid/liquid heptane/acetonitrile biphasic separation. The recovered IBX reagent could then be regenerated and used in multiple cycles for oxidation of both primary and secondary alcohols.
