Synthesis of racemic β-chamigrene, a spiro[5.5]undecane sesquiterpene [corrected]

Simen Antonsen; Lars Skattebøl; Yngve Stenstrøm

doi:10.3390/molecules191220664

Synthesis of racemic β-chamigrene, a spiro[5.5]undecane sesquiterpene [corrected]

Molecules. 2014 Dec 10;19(12):20664-70. doi: 10.3390/molecules191220664.

Authors

Simen Antonsen¹, Lars Skattebøl², Yngve Stenstrøm³

Affiliations

¹ IKBM, P.O. Box 5003, NMBU, The Norwegian University of Life Sciences, N-1430 Ås, Norway.
² Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway.
³ IKBM, P.O. Box 5003, NMBU, The Norwegian University of Life Sciences, N-1430 Ås, Norway. yngve.stenstrom@nmbu.no.

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.

MeSH terms

Cycloaddition Reaction
Cyclohexanones / chemistry*
Ketones / chemistry*
Microwaves
Sesquiterpenes / chemical synthesis*
Stereoisomerism

Substances

Cyclohexanones
Ketones
Sesquiterpenes
beta-chamigrene
methylheptenone