Abstract:Twenty two 2-(4-aryloxyphenoxy)propionic acid derivatives were designed and synthesized from (R)-2-(4-hydroxyphenoxy) propanoic acid, and their structures were characterized by 1HNMR, 13CNMR, HRMS or elemental analysis. The bioassay results indicated that most of the compounds exhibited excellent activities and selectivities against monocotyledonous weeds at 75 g/hm2. In particular, compounds Ⅳa, Ⅳc, Ⅳf, Ⅳg and Ⅳi exhibited 100% herbicidal efficiency in both pre- and postemergence treatments against Digitaria sanguinalis, Echinochloa crus-galli L and Setaria viridis.