A novel cis-selective cyclohexanone annulation as the key step of a total synthesis of the sesquiterpene isoacanthodoral.
Isoacanthodoral (1) is a structurally unique sesquiterpene in that it is a bicyclo[4.4.0]dec-1-ene with a cis- rather than the common trans-junction between the constituting rings. An efficient construction of this motif has been accomplished by a novel cis-selective cyclohexanone annulation, combining the lithium enolate of ester 8, the alpha,beta-unsaturated ester 6, and vinylmagnesium bromide in a single synthetic operation. For completing the total synthesis of 1, a Shapiro-olefination/hydrogenation sequence and a reductive cyanation were employed.
Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg im Breisgau, Germany.
Thomas
T
Hampel
Reinhard
R
Brückner
D002384:Catalysis; D003512:Cyclohexanones / Q000737:chemistry*; D015394:Molecular Structure; D012717:Sesquiterpenes / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D003512:Cyclohexanones; D012717:Sesquiterpenes; C489770:acanthodoral; C036468:cyclohexanone