Kende for a gift of the methyl ester of 1,2-dipropylcyclopropene-3carboxylic acid. chlorate in 25 ml of anhydrous ether was treated with a solution of 0.0368 g (0.965 mmol) of lithium aluminum hydride in 10 ml of ether. The reaction was stirred 0.5 hr under nitrogen at room temperature, cooled in an ice bath, and hydrolyzed by dropwise addition of water. The crude reaction product was filtered, diluted with two 25-ml portions of ether, and dried over magnesium sulfate.Removal of ether afforded a viscous oil which was subjected to Kragen tube distillation (oil bath temperature 80-120" (8 mm)). The product was identified as 1,2,3-tri-t-butylcyclopropene (8) from the following data: infrared spectrum: v::: (cm-1) 2960 (s), 2900 (m), 2865 (m), 1835 (w), 1475 (m), 1465 (m), 1395 (m), 1365 (m), 1355 (w), and 1275 (w); mass spectrum: m/e 208, 207, and 151; nmr spectrum: 0. 82 (9 H, s), 1.16 (18 H, s) 1.37, (1 H, s). An acceptable analysis could not be obtained for this compound. 168 Anal. Calcd for C16H~s: C, 86.46; H, 13.54. Found: C, 85.66; H, 13.57. Reaction of Cation 5d with r-Butyllithium. A suspension of 0.0962 g (0.314 mmol) of tri-t-butylcyclopropenyl perchlorate in 25 ml of anhydrous benzene was prepared under nitrogen and quenched The Syntheses of the ( -)-CY-and ( +)-P-cis-Bergamotenes'Abstract: Syntheses of (-)-a-cis-bergamotene (2) a n d (+)-0-cis-bergamotene (3) from (-)+-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) a n d black pepper (Piper nigrum L.). T h e isomer 3 was found t o be different from an isolate of Indian valerian oil (Valeriana wallichi) which has been assigned this structure.he structure 1 has been proposed for a sesquiterpene Mr. Wenninger for his generosity in providing us with samples of acis-, a-trans-, and P-trans-bergamotenes.
