New pathways in transannular cyclization of germacrone [germacra-1(10),4,7(11)-trien-8-one]: evidence regarding a concerted mechanism.
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.
Barrero
Alejandro F
AF
Department of Organic Chemistry, Institute of Biotechnology, University of Granada, Avda. Fuente Nueva, s/n, 18071 Granada, Spain. afbarre@ugr.es
Herrador
M Mar
MM
López-Pérez
José-Luis
JL
Arteaga
Jesús F
JF
Catalán
Julieta
J
D003500:Cyclization; D015394:Molecular Structure; D045788:Sesquiterpenes, Germacrane / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D045788:Sesquiterpenes, Germacrane; C048393:germacrone