What is the IUPAC name for the molecule shown below?
A) (
E)-4-isopropyloct-3-en-5-yne
B) (
Z)-4-isopropyloct-3-en-5-yne
C) (
E)-5-isopropyloct-5-en-3-yne
D) (
Z)-5-isopropyloct-5-en-3-yne
E) (
E)-4-(2-methylethyl)oct-3-en-5-yne

Question

What is the IUPAC name for the molecule shown below? 
A) (
E)-4-isopropyloct-3-en-5-yne 
B) (
Z)-4-isopropyloct-3-en-5-yne 
C) (
E)-5-isopropyloct-5-en-3-yne 
D) (
Z)-5-isopropyloct-5-en-3-yne 
E) (
E)-4-(2-methylethyl)oct-3-en-5-yne

Quizplus · Accepted Answer

The longest continuous chain in the molecule contains 8 carbon atoms. The triple bond between carbon atoms 3 and 4 takes priority over the double bond between carbon atoms 5 and 6. The substituent on carbon atom 4 is an isopropyl group. The double bond has two possible configurations, but since the highest priority groups on either side of the double bond (the triple bond) are both on the same side of the molecule, the correct configuration is (Z). Therefore, the correct IUPAC name is (Z)-4-isopropyloct-3-en-5-yne.

What Is the IUPAC Name for the Molecule Shown Below