Terpenoids : Part Ill. A New Synthesis of dl-Calamenene

Synthesis of dl-calamenene has been achieved. 1, 6-Dimethy1-4-acetyl-1, 2, 3, 4-tetrahydronaph­thalene, obtained through Diels Alder reaction of \(α-p\)-dimethyl styrene and methyl vinyl ketone, has been converted to 1, 6-dimethy1-4(ethyl- 1'-bromo)-1, 2, 3, 4-tetrahydronaphthalene. The latter bromide, on submission to lithium-dimethyl copper in tetrahydrofuran, affords the terpenic hydrocarbon