Show how you would use the Friedel–Crafts acylation, Clemmensen reduction, and/or Gatterman–Koch synthesis to prepare the following compounds:
g. n-butylbenzene

Verified step by step guidance

1. Start by analyzing the target molecule, n-butylbenzene. It consists of a benzene ring attached to a straight-chain butyl group (C4H9). The goal is to introduce this alkyl group onto the benzene ring.
2. Use Friedel–Crafts acylation to introduce a four-carbon chain with a carbonyl group (butanoyl group) onto the benzene ring. This reaction involves reacting benzene with butanoyl chloride (CH3CH2CH2COCl) in the presence of a Lewis acid catalyst such as AlCl3. The product will be 1-phenyl-1-butanone (C6H5COCH2CH2CH3).
3. Next, perform a Clemmensen reduction to convert the carbonyl group in 1-phenyl-1-butanone to a methylene group (-CH2-). This reduction is carried out using zinc amalgam (Zn(Hg)) and concentrated hydrochloric acid (HCl). The product will be n-butylbenzene (C6H5CH2CH2CH2CH3).
4. Alternatively, you could use the Gatterman–Koch synthesis to introduce a formyl group (-CHO) onto the benzene ring, followed by chain elongation reactions to achieve the n-butyl group. However, this approach is less direct and involves additional steps.
5. Verify the structure of the final product, n-butylbenzene, to ensure that the desired substitution pattern has been achieved. The benzene ring should be attached to a straight-chain butyl group (C4H9) without any branching or additional functional groups.

Key Concepts

Friedel–Crafts Acylation

Friedel–Crafts acylation is an electrophilic aromatic substitution reaction that introduces an acyl group into an aromatic ring. This reaction typically uses an acyl chloride and a Lewis acid catalyst, such as aluminum chloride, to form a ketone. The acyl group enhances the reactivity of the aromatic compound, allowing for further transformations, making it a valuable method for synthesizing substituted aromatic compounds.

Clemmensen Reduction

The Clemmensen reduction is a chemical reaction that reduces carbonyl groups (aldehydes and ketones) to alkanes using zinc amalgam and hydrochloric acid. This method is particularly useful for converting aromatic ketones into the corresponding alkylated aromatic compounds without affecting other functional groups. It is a key reaction in organic synthesis for simplifying complex molecules.

Gatterman–Koch Synthesis

The Gatterman–Koch synthesis is a method for synthesizing aromatic aldehydes through the formylation of aromatic compounds using carbon monoxide and hydrochloric acid in the presence of a Lewis acid catalyst. This reaction allows for the introduction of a formyl group (-CHO) into the aromatic ring, which can then be further manipulated in subsequent reactions, making it a powerful tool in organic synthesis.