Conjugated Hydrohalogenation (1,2 vs 1,4 addition) Practice Problems

Explain why cyanide does 1,2-addition instead of 1,4-addition in the reaction given below.

No matter whether the reaction is done under kinetic (0 °C) or thermodynamic (100 °C) control, the following diene produces the same result. Draw the plausible product(s) and explain your observation.

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Analyze the nucleophiles listed below to see whether they would undergo 1,2- or 1,4-addition.

Draw the products of the following reaction. Ignore stereoisomers.

A chemist wanted to investigate whether the faster formation of the 1,2-addition product in the reaction of 1,3-butadiene with HBr was due to the greater proximity of the nucleophile to the C-2 carbon in the transition state. Should he investigate the reaction using 1-methylcyclopenta-1,3-diene or 2-methylcyclopenta-1,3-diene?

Draw the 1,2- and 1,4-addition products in the reaction of the below-given compound with HBr and label them as the kinetic and the thermodynamic products. Do not include stereoisomers.

Draw the 1,2- and 1,4-addition products in the reaction of the below-given compound with HBr and label them as the kinetic and the thermodynamic products. Do not include stereoisomers.

a. Show how a hydrocarbon can produce the following compound in a single step.
b. What other product would be formed from this reaction?

Draw the products obtained in the reaction of cyclohepta-1,3,5-triene with one equivalent of HBr and label them as the kinetic and the thermodynamic products. Do not include stereoisomers.

The following reaction shows that the proximity of the bromide ion to carbon-2 in the transition state is the reason why the 1,2-addition product is formed at a higher rate.
Explain why it was necessary to know that the reaction was performed under kinetically controlled conditions.

Identify which double bond of myrcene is more reactive towards the electrophilic addition of HBr.

Draw the products of the following reaction. Ignore stereoisomers.

Draw the products obtained in the reaction of the following compound with one equivalent of HBr and label them as the kinetic and the thermodynamic products. Do not include stereoisomers.

The reaction of 1 mol of 4-methylpenta-1,3-diene with 1 mol of HBr produces a mixture of the following three products: 4-bromo-2-methylpent-2-ene, (E)-4-bromo-4-methylpent-2-ene, and (Z)-4-bromo-4-methylpent-2-ene. Write a mechanism that accounts for the formation of these products.

Propose the structures of the products in the reaction given below.
buta-1,3-diene + bromine in CCl₄

Propose the structures of the products in the reaction given below.
cyclohexa-1,3-diene + HBr (anhydrous)

Propose the structures of the products in the reaction given below.

hexa-2,4-diene + bromine water