TOPIC: 23. Lipids

SUBTOPIC: 232. Terpenes

5072

Using conventional organic reaction mechanisms, rationalize the fact that a single progenitor, geraniol pyrophosphate, can give rise to a large variety of different terpenes and terpene derivatives. Illustrate this idea using limonene and 1,8-cineole.

Geraniol Pyrophosphate Limonene 1,8-Cineole

5131

Acetate is not the only biogenetic building block for the long chain of fatty acids. From 50 million year old oil shale, as well as from modern organisms, there has been isolated 3,7,11,15-tetramethylhexadecanoic acid

Illustrate the familiar structural unit which occurs here.

5164

Circle the isoprene units in each of the following terpenes.

5165

Write a mechanism for the acid catalyzed transformation of farnesol to bisabolene:

farnesol bisabolene

5191

When the terpene limonene is treated with oxygen while being irradiated with light in the presence of a small amount of benzophenone, the hydroperoxide is formed. Write a mechanism involving singlet oxygen that will account for the formation of the hydroperoxide.