Question 23.7: Identifying and Drawing Cis–Trans Isomers Which of the molec...
Identifying and Drawing Cis–Trans Isomers
Which of the molecules (a–c) can exhibit cis–trans isomerism? For those that have this type of isomer, show the line drawing of the corresponding cis or trans isomer.
STRATEGY
It is often easier to visualize organic line drawings by converting them back into structural formulas. The presence of cis–trans isomerism exists when each carbon atom in a double bond has two different substituents attached.
(a) Cis–trans isomers exist because the Br atoms can be placed on the same side or on opposite sides of the double bond.
(b) This structure has two -CH_{3} (methyl) groups bonded to the same C atom, therefore cis–trans isomers do not exist.
(c) Cis–trans isomers exist because each carbon has two different substituents attached.
