Chapter 9.2, Problem 4ATS

Interpretation Introduction

Interpretation:

A systematic IUPAC name and stereo descriptor for the given compound have to be provided.

Concept Introduction:

Nomenclature of alkynes:

• The parent of alkyne is identified by longest chain that includes $\text{C}\equiv \text{C}$ bond.
• The parent name of alkyne has suffix of “yne” which indicates presence of $\text{C}\equiv \text{C}$ in it.
• While numbering the parent chain, lowest number should goes to triple bond even in presence of different alkyl substituents.
• The substituents in alkyne are assembled alphabetically.

R and S nomenclature: it is used to assign the molecule using CIP (Cahn-Ingold-Prelog) rules.

The CIP rules are as follows:

Select the chiral carbon and assign the numbers according to the decreasing atomic mass of atoms attached to it.

If the numbering follows clockwise direction then the molecule is termed as R and if it follows anti-clockwise direction then molecule is termed as S.