Furan-site transformations of obacunone as potent insecticidal agents

Furan ring is a key pharmacophore for insecticidal activity of limoninoids. To develop natural-product-based insecticidal agents, a series of furan-site transformations (2, 3 and 3a–j) of obacunone were synthesized by selective bromination and following coupling reactions without altering other functional groups. Bioassays indicated that derivatives 3e, 3f and 3j displayed more potent insecticidal activity than obacunone and toosendanin against the instar larvae of Mythimna separate Walker. Besides, their structure–activity relationships were discussed