Immobilization of TEMPO onto Polystyrene Resin

Significance

A simple and efficient method for the preparation of a new polystyrene-supported TEMPO by using click chemistry was described. Propargylation of commercially available 4-hydroxy-TEMPO 1 led to propargyl ether TEMPO 2. TEMPO 2 was readily grafted by the copper(I)-cata­lyzed azide-alkyne cycloaddition onto polystyrene resin to give PS-CLICK-TEMPO 3. The new heterogeneous PS-CLICK-TEMPO 3 promoted the selective oxidation of aliphatic and benzylic alcohols with sodium hypochloride as terminal oxidant and KBr as co-catalyst (92-99% yield). Catalyst 3 was readily recovered by filtration and reused for the next cycle without further activation in five subsequent runs employing 4-methylbenzyl alcohol as substrate (92-95% yield).