Using Soluble Polymer Supports To Facilitate Homogeneous Catalysis

A review of various research studies conducted since 2002 on the use of soluble polymer supports to facilitate homogeneous catalysis is presented. TEMPO is a commonly used organocatalyst for the selective oxidation of primary alcohols to aldehydes. Use of PEG-supported proline as a catalyst is described in enantioselective conjugate addition reactions. A phosphonium salt is described and is found to deliver catalyzed formation of cyclic carbonates, while intermediate cyclic carbonates could be used without isolation as a phosgene-equivalent. The synthesis of three types of PEG-supported salen ligands could be used to catalyze the addition of diethyl zinc to aldehydes. A study including the use of PEG supports to prepare a tartate ester library is an effort to probe the effect of tartrate structure on stereoselectivity in Sharpless asymmetric epoxidation of allylic alcohols.