title: Synthesis of racemic β-chamigrene, a spiro[5.5]undecane sesquiterpene [corrected].
abstract: The present paper describes a total synthesis of racemic β-chamigrene, a sesquiterpene with a spiro[5.5]undecane carbon framework. Compared with previously reported β-chamigrene syntheses, we were able to reduce the total number of reaction steps, which also resulted in a significant improvement of the overall yield. The commercially available ketone 6-methylhept-5-en-2-one was transformed by known simple procedures into 3,3-dimethyl-2-methylenecyclohexanone. This reacted with isoprene by a Diels-Alder reaction to give a spiro ketone. An olefination reaction on this compound gave the target molecule.
authors.affiliation: IKBM, P.O. Box 5003, NMBU, The Norwegian University of Life Sciences, N-1430 Ås, Norway.
authors.forename: Simen
authors.initials: S
authors.lastname: Antonsen
authors.affiliation: Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway.
authors.forename: Lars
authors.initials: L
authors.lastname: Skattebøl
authors.affiliation: IKBM, P.O. Box 5003, NMBU, The Norwegian University of Life Sciences, N-1430 Ås, Norway. yngve.stenstrom@nmbu.no.
authors.forename: Yngve
authors.initials: Y
authors.lastname: Stenstrøm
mesh_terms: D061565:Cycloaddition Reaction; D003512:Cyclohexanones / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D008872:Microwaves; D012717:Sesquiterpenes / Q000138:chemical synthesis*; D013237:Stereoisomerism
chemical_list: D003512:Cyclohexanones; D007659:Ketones; D012717:Sesquiterpenes; C000600620:beta-chamigrene; C029750:methylheptenone