Evaluation of the Elbs Persulfate Oxidation Reaction for the Preparation of Aryloxyphenoxypropionate Herbicides

Abstract

A new, simple method for the preparation of several 4-( aryloxy )phenols (2a-d) and alkyl 2-(4-hydroxyphenoxy)propionates (3a,b) is described. These compounds are key precursors for the synthesis of important aryloxyphenoxypropionate herbicides (1a-d). The method uses the Elbs persulfate oxidation to convert phenol into 4-hydroxyphenyl sulfate (5). The free hydroxy group is then reacted with various aryl halides and alkyl 2-halopropionates. Mild hydrolysis of the sulfate group with boiling acetic acid then gives the products (2a-d) and (3a,b), generally in modest to good yield.