Terpinolene epoxide

This comparatively recently described compound is a natural product, occurring in Japanese pepper and Citrus Junes oil, and has also been obtained by Leffingwell from terpinolene epoxide (115) by ring opening of the epoxide with dimethylamine, then thermolysis of the V-oxide. Raney nickel catalysed selective hydrogenation of metha-l,8-dien-4-ol (112) leads to the widely occurring menth-l-en-4-ol (116). ... 

Cycloheptanes.—One synthesis of karahanaenone (231) depends upon thermal rearrangement of a 2-methylene-5-vinyltetrahydrofuran, and the conditions for this type of reaction have been examined on a simpler model (232), which arises from the dihydrofuran (233) at 140—200 °C. The reaction to the cycloheptenone (234) occurs rapidly at active sites on a glass surface, but is arrested in tubes coated with sodium hydroxide. Higher temperatures and lower pressures give two other compounds (235) and (236). All these reactions involve the biradical (237), as does the conversion of the cyclopropane (238) into the cycloheptenone (234). Karahanaenone (231) has also been made by isomerization of terpinolene epoxide (239) with boron trifluoride etherate. Eucarvone (240 R = H) should not be... 

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