Question

Question: Devise a synthesis of CH₂ CH₂CH₂CH₂Br from HC$\equiv$CH You may use any other required organic or inorganic reagents.

Short answer

Answer

Step-by-step solution

 Step 1: Reagents required for the synthesis

The synthesis reaction takes place in the presence of these reagents:

• NaH: abstraction of an acidic proton
• CH₃CH₂ Br: addition of alkyl group
• Lindlar catalyst: reduction of alkyne to cis-alkene
• HBr in the presence of peroxide: radical mechanism giving alkyl halide from an alkene

Stepwise mechanism

Step 1

Acidic hydrogen abstraction by NaH base

Step 2

Substitution of the alkyl group

Step 3

Reduction of alkyne

Step 4

Formation of alkyl halide following anti-Markovnikoff’s rule