Engineering
Chemistry
Nucleophilic Substitution
Preparation of Alkyl Halide
Free radical
Question

CH142=CHCH3NBSCCl4,Δ Nadryether,ΔProducts.
Products can be

CH2 = CH – CH2–CH2–CH = CH2

CH142=CHCH2CH2CH=CH142

CH2=CHCH142CH142CH=CH2

CH2=CHCH142CH2CH=CH142

JEE Advance
College PredictorLive

Know your College Admission Chances Based on your Rank/Percentile, Category and Home State.

Get your JEE Main Personalised Report with Top Predicted Colleges in JoSA

Solution

This question involves the Wurtz reaction and allylic bromination. The reactant is propene (CH3-CH=CH2). NBS/Δ performs allylic bromination, giving 3-bromopropene (CH2=CH-CH2Br). This alkyl halide then undergoes the Wurtz reaction with Na/dry ether, where two molecules couple to form a symmetrical product.

The Wurtz reaction: 2RXNa, dry etherRR

For 3-bromopropene (R = CH2-CH=CH2), the symmetrical coupled product is CH2=CH-CH2-CH2-CH=CH2 (1,5-hexadiene).

Final Answer: CH2 = CH – CH2–CH2–CH = CH2