SYNTHESES OF (-)-ALPHA-AND (+)-BETA-CIS-BERGAMOTENES

Syntheses of (–)-α-cis-bergamotene (2) and (+)-β-cis-bergamotene (3) from (–)-β-pinene are described. The isomer 2 was shown to be identical with a sesquiterpene hydrocarbon isolated from oils of opoponax (Commiphora erythraea var. glabrescens Engler) and black pepper (Piper nigrum L.). The isomer 3 was found to be different from an isolate of Indian valerian oil (Valeriana wallichi) which has been assigned this structure. © 1969, American Chemical Society. All rights reserved.