Chapter 14.2, Problem 3P

Interpretation Introduction

Interpretation:

Looking at the possible catrbocation intermediates produced during the addition of HCl to 1,3-pentadiene, which adduct 1,2- or 1,4- will be formed as the predominant product is to be stated.

Concept introduction:

Conjugated dienes undergo electrophilic addition reactions through the formation of an allyl carbocation. The allyl cation is resonance stabilized and the attack of bromide ion on each of these forms leads to the formation of a mixture of 1,2- and 1,4-addition products. The more stable form of the allyl cation will yield the major product.

To state:

Which adduct, 1,2- or 1,4-, will be formed as the predominant product during the addition of HCl to 1,3-pentadiene, by looking at the possible catrbocation intermediates in the reaction.