Question

Does a coupling reaction have to be used to synthesize p-dipropylbenzene?

Yes, the reaction has to be used as the propyl group is a meta director, so m-dipropylbenzene would be obtained.

Yes, the reaction has to be used as the propyl group is a meta director, so propylbenzene cannot undergo a Friedel-Crafts reaction.

No, the reaction does not have to be used as the propyl group is an ortho-para director, so p-dipropylbenzene can be obtained in two steps using butyl chloride.

No, the reaction does not have to be used as the propyl group is an ortho-para director, so propylbenzene can undergo a Friedel-Crafts reaction.

Part B

Can a coupling reaction be used to synthesize p-dipropylbenzene?

No, the reaction cannot be used as bromination would occur at the meta-position.

Yes, the reaction can be used. In such case bromination occurs before the reduction of the carbonyl group.

Yes, the reaction can be used. In such case bromination occurs after the reduction of the carbonyl group.

No, the reaction cannot be used. Only m-dipropylbenzene can be obtained with the help of a coupling reaction.

Answer 1

Part A

No, the reaction does not have to be used as the propyl group is an ortho-para director, so propylbenzene can undergo a Friedel-Crafts reaction

The Alkyl substituents are Ortho and Para directors.

The first step is alkylation of Benzene to yield Propyl benzene

The second step is Alkylation of Propyl benzene to yield P-dipropylbenzene,since the alkyl subtituents in Benzene ring are Ring activating groups the substitution takes place in Ortho and Para.

P-dipropylbenzene is the major product obtained than O-dipropylbenzene because it is less stable.