Q.67. - Organic Chemistry

Question

Question:Devise a synthesis of 1-phenyl-5-methylhexane $\left[C_6{H}_5{\left(C{H}_2\right)}_{4}CH{\left(C{H}_3\right)}_2\right]$ from acetylene, alkylhalides, and any required inorganic reagents.

Step-by-Step Solution

Answer

Answer

Step 1: Reaction of acetylene with isopropyl bromide

Acetylene is treated with a strong base to form an acetylide anion, which can further react with an alkyl halide to form a new alkyne. Using this mechanism, acetylene is treated with sodium hydride and then reacted with isopropyl bromide.

 

The reaction is shown below:

Formation of 1-phenyl-5-methyl-hex-3-yne

Step 3: Reduction of 1-phenyl-5-methyl-hex-3-yne

The alkyne formed in the previous step is reduced to 1-phenyl-5-methylhexane upon treatment with hydrogen in the presence of a palladium catalyst. The reaction is shown below:

Formation of 1-phenyl-5-methylhexane