Synthesis and Herbicidal Activity of Cyperin

Cyperin is a phytotoxic diphenyl ether natural product. Total synthesis of cyperin has been achieved and its herbicidal activity evaluated. The synthesis is highlighted by an Ullmann coupling to construct the diphenyl ether moiety contained within cyperin. It was found that cyperin inhibited root growth of Cyperus rotundus grown on agar, however, root growth of Cyperus grown in soil was unaffected. Cyperin also inhibited growth of Arabidopsis thaliana and Agrostis palustris grown in agar. The mode of action of cyperin is different from that of commercial diphenyl ether herbicides that inhibit protoporphyrinogen oxidase