Chapter 13, Problem 13.58EP

Interpretation Introduction

Interpretation:

The IUPAC name of the molecule whose common name is isoprene has to be given.

Concept Introduction:

IUPAC nomenclature for alkene:  There are about eight rules to be followed in giving IUPAC name for alkene.

• The suffix –ane has to be replaced with the suffix –ene.  This is used to indicate the presence of double bond.
• The longest continuous chain of carbon atoms has to be chosen that contains both carbon atoms of the double bond.
• The parent carbon chain has to be numbered in a way so that the numbering begins at the end near to the double bond.  In case if the double bond is equidistant from both ends, then numbering has to be done from the end that is closer to substituents.
• The position of the double bond has to be given a single number which is lower‑numbered carbon atom that is present in the double bond.
• Suffixes like –diene, -triene, -tetrene, and so on are used when the compound contains more than one double bond.
• In case of cycloalkenes which do not have any substitution, the numbering is not needed to locate the double bond because the bond is assumed to be between the carbons 1 and 2.
• In case if substituents are present in cycloalkene, then the double‑bonded carbon atoms are numbered 1 and 2 in a direction where the substituent gets the lower number.
• If the cycloalkenes contain more than one double bond, then one double bond is assigned the numbers 1 and 2 followed by the other double bond so that the lowest number possible is given.