title: New pathways in transannular cyclization of germacrone [germacra-1(10),4,7(11)-trien-8-one]: evidence regarding a concerted mechanism.
abstract: The transannular cyclization of germacrone with HSO(3)Cl at -78 degrees C by means of a concerted and regioselective mechanism gives rise to a bicyclo[6.2.0]decan-2-ylium intermediate ion, which evolves to unusual skeletons through subsequent cyclization and Wagner-Meerwein rearrangements. This novel germacra-1(10),4-diene cyclization could suggest the existence of a new biosynthetic pathway to sesquiterpenes.
authors.affiliation: Department of Organic Chemistry, Institute of Biotechnology, University of Granada, Avda. Fuente Nueva, s/n, 18071 Granada, Spain. afbarre@ugr.es
authors.forename: Alejandro F
authors.initials: AF
authors.lastname: Barrero
authors.forename: M Mar
authors.initials: MM
authors.lastname: Herrador
authors.forename: José-Luis
authors.initials: JL
authors.lastname: López-Pérez
authors.forename: Jesús F
authors.initials: JF
authors.lastname: Arteaga
authors.forename: Julieta
authors.initials: J
authors.lastname: Catalán
mesh_terms: D003500:Cyclization; D015394:Molecular Structure; D045788:Sesquiterpenes, Germacrane / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D045788:Sesquiterpenes, Germacrane; C048393:germacrone