Naming Stereoisomeric Alkenes by the E-Z Notational System

FIGURE 5.2 Interconversion of c/s- and trans-2-butene proceeds by cleavage of the ir component of the double bond. The red balls represent the two methyl groups. 

When the groups on either end of a double bond are the same or are structurally similar to each other, it is a simple matter to describe the configuration of the double bond as cis or trans. Oleic acid, for example, a material that can be obtained from olive oil, has a cis double bond. Cinnamaldehyde, responsible for the characteristic odor of cinnamon, has a trans double bond. 

PROBLEM 5.5 Female houseflies attract males by sending a chemical signal known as a pheromone. The substance emitted by the female housefly that attracts the male has been identified as c/s-9-tricosene, C23H46. Write a structural formula, including stereochemistry, for this compound. 

CHAFER FIVE Structure and Preparation of Alkenes Elimination Reactions 

The priority rules were developed by R. S. Cahn and Sir Christopher Ingold (England) and Vladimir Prelog (Switzerland) in the context of a different aspect of organic stereochemistry they will appear again in Chapter 7. 

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