Full stereochemical assignment and synthesis of the potent anthelmintic pyrrolobenzoxazine natural product CJ-12662.

The structure of the unusual anthelmintic pyrrolobenzoxazine terpenoid natural product CJ-12662 was established by X-ray crystallography and partial synthesis from 2-chloronitrobenzene. An unusual Meisenheimer-type rearrangement was used to provide the core pyrrolobenzoxazine heterocycle, and coupling of a tetracyclic pyrrolobenzoxazine lactone with the terpene alcohol was used to complete the synthesis of CJ-12662.