title: Sequential one-pot cyclizations: concise access to the ABCE tetracyclic framework of strychnos alkaloids.
abstract: A sequential one-pot biscyclization route to the ABCE tetracyclic framework of Strychnos alkaloids has been developed. Specifically, the AgOTf-mediated spirocyclization of an appropriately functionalized indole 3-carbinamide afforded a stable spiroindolenine intermediate; subsequent addition of DBU to the reaction mixture effected an unprecedented intramolecular aza-Baylis-Hillman reaction, delivering a tetracyclic product in 70% isolated yield.
authors.affiliation: Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122.
authors.forename: Gopal
authors.initials: G
authors.lastname: Sirasani
authors.forename: Rodrigo B
authors.initials: RB
authors.lastname: Andrade
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D003500:Cyclization; D015394:Molecular Structure; D031451:Strychnos / Q000737:chemistry*
chemical_list: D000470:Alkaloids