Polymer-supported reducing and oxidising reagents

Polymer-supported reagents have the potential to yield very clean product with no purification needed. Solid-supported silane reagents were studied for the reduction of ester to the corresponding aldehyde or ketone. A commercially PS-DES resin was tested in the catch and release reduction of ester. A new silane resin was successfully synthesised in two steps. Unfortunately, an efficient procedure could not be found to perform the first part of the reduction, the hydrosilylation. A protocol for the Tamao-Fleming oxidation was then devised with the new silane resin as its main reagent. Again the hydrosilylation of alkene seemed to be the limiting step. Several polymer-bound IBX derivatives were then synthesised. The oxidation of alcohols proved to be successful despite a modest loading of the first IBX resin. Finally, an efficient three step synthesis of an IBX amide resin with a good loading and reactivity comparable to IBX was devised. A very good method to remove all trace of tetrabutylammonium species from the IBX resins was discovered.