The reactivity of the tricyclic enone, (+)-(1S, 2R, 4R, 7R)-3, 3, 7-trimethyltricyclo[6.3.0.0^{2, 4}]undec-8-en-10-one(1), obtained previously as the key intermediate for the synthesis of compounds bearing the aromadendrane uncleus was investigated, and a natural aromadendrane-type sesquiterpene, (+)-1, 2-didehydroaromadendrane (2), was synthesized via regio- and stereo-specific introduction of a methyl group at the C-11 position of 1 followed by reductive deoxygenation.