Q.68. - Organic Chemistry

Question

Question: Devise a synthesis of (3R,4S)-3,4-dichlorohexane from acetylene and any needed organic compounds or inorganic reagents.

Step-by-Step Solution

Answer

Answer

Step 1: Conversion of acetylene to hex-3-yne

Acetylene can be converted to acetylide anion upon treatment with a strong base, which makes them a reagent for nucleophilic substitution.

Based on this theory, acetylene is converted to hex-3-yne as shown below:

Formation of hex-3-yne from acetylene

Step 2: Synthesis of (3R , 4 S )-3,4-dichlorohexane from hex-3-yne

Hex-3-yne can be treated with sodium in liquid ammonia to reduce it to hex-3-ene via anti-addition of hydrogen. Further anti-addition of chlorine to the alkene leads to the formation of (3R,4S)-3,4-dichlorohexane. The reaction is given below:

Synthesis of (3R,4S)-3,4-dichlorohexane from hex-3-yne