Allylic Halogenation Practice Problems

Show how you could synthesize oct-4-ene starting from bromoethane and using an alkenyl halide with no more than four carbons.

Draw the substitution and elimination products formed in the following reaction:

1-(bromomethyl)-2-methylcyclohex-1-ene heated with methanol

Provide a suitable allylic halide and a Grignard reagent that could be used to produce 1-isopentylcyclohex-1-ene.

Provide a suitable allylic halide and a Grignard reagent that could be used to synthesize (E)-1-(but-2-en-1-yl)-1-methylcyclopentane.

In the addition reaction of Cl₂ to buta-1,3-diene at low temperatures, it produces 60 % of product A and 40 % of product B. However, when the same reaction is carried out at a higher temperature, the product ratio changes to 10 % of A and 90% of B.

(a) Propose a mechanism for this reaction and show the structures of products A and B.

(b) Explain why product A is predominant at low temperatures, while product B is favored at high temperatures.

A chemist is working on the synthesis of a new compound. He starts with the conversion of 3-chloro-6-ethylcyclohex-1-ene into alcohol A as shown below. This alcohol undergoes subsequent processes to obtain the desired new compound. Illustrate how 3-chloro-6-ethylcyclohex-1-ene can be converted into alcohol A.