Cis-Trans Isomers

<< Introduction to Organic Chemistry

 

Draw pair of cis-trans isomers

 

Prerequisite Knowledge

• Stereoisomerism (geometric/optical)

 

Approach

• Locate the region of restricted rotation i.e. C=C. Hold one end still; flip groups at the other end.

• Common mistake 1: flip at both ends

• Common mistake 2: flip across C=C

 

Practice

 

Draw the structures of the cis-trans isomers for each compound. Label them cis and trans.

• 3-hexene

• 2-bromo-3-methylpent-2-ene

• 2-butenoic acid (CH₃CH=CHCOOH)

• 1,2-dimethylcyclopropane