Chapter B, Problem B.3P

Interpretation Introduction

Interpretation:

The IUPAC name for the given compound is to be determined.

Concept introduction:

In case of molecules containing a $\text{C=C }$ or $\text{C}\equiv \text{C}$ bond, the longest continuous carbon chain or largest ring that contains the double or triple bond is considered as the root. It is possible that the longest carbon chain has more carbons than specified by the root. But the double or triple bond must be a part of the root. The root is named from the name of the analogous alkane or cycloalkane by replacing the suffix ane by ene if a double bond is present. The suffix ane is replaced by yne if a triple bond is present.

If the root is a chain, the numbering begins from that end of the chain, which encounters the $\text{C=C }$ or $\text{C}\equiv \text{C}$ at the earliest. If there is a tie, then the chain is numbered such that the substituents get the lowest locator numbers.

If the root is a ring, then the double or triple bonded carbon atoms are always numbered as C1 and C2. This must be done such that the locator numbers for the substituents are minimized. The lower of the two locator numbers for the $\text{C=C }$ or $\text{C}\equiv \text{C}$ is written before the ene or yne suffix. Prefixes and locator numbers are used for the substituents attached.