Q.61. - Organic Chemistry

Question

Question: Devise a synthesis of muscalure, the sex pheromone of the common housefly, from acetylene and any other required reagents.

                                                  Muscalure

Step-by-Step Solution

Answer

Answer:

Step 1: Deprotonation

The organic reaction in which a proton is removed from the compound with the help of a strong base such as sodium or potassium hydride is known as a deprotonation reaction.

The acetylene is deprotonated by the strong base sodium hydride to produce sodium acetylide.

Deprotonation of Acetylene

Step 2: Substitution reaction

The strong base sodium acetylide would undergo a substitution reaction with bromononane to replace bromine with the acetylide anion.

Substitution reaction.

Step 3: Deprotonation and substitution

This compound is again treated with another molecule of sodium hydride, followed by bromotridecane, to form a substituted alkyne. 

Deprotonation followed by substitution

Step 4: Reduction reaction

The corresponding alkyne is reduced with hydrogen in the presence of Lindlar’scatalyst to form the cis alkene (Z)-9-tricosene.

Reduction of alkyne to alkene