Synthesis of Osthole Derivatives with Grignard Reagents and Their Larvicidal Activities on Mosquitoes

The structure of osthole has been modified to improve its larvicidal activity against mosquitoes. A new efficient synthesis of osthole derivatives with Grignard reagents has been developed, which employs CuI and LiCI as pro- moters and covers a broad range of substrates to afford the corresponding products in mild to good yields （up to 83%）. Bio-activity evaluation showed that several products exhibited better activities than osthole.