Show how you might synthesize the following compounds starting with bromobenzene, and alkyl or alkenyl halides of four carbon atoms or fewer.


(c) dec-5-ene

Verified step by step guidance

1. Identify the target molecule, dec-5-ene, which is a 10-carbon chain with a double bond between the 5th and 6th carbon atoms.
2. Plan the synthesis by considering the starting materials: bromobenzene and alkyl or alkenyl halides with four or fewer carbon atoms.
3. Use a Grignard reaction to form a carbon-carbon bond. First, convert bromobenzene to phenylmagnesium bromide by reacting it with magnesium in dry ether.
4. Select an appropriate alkyl halide, such as 1-bromobutane, to react with the Grignard reagent to extend the carbon chain. This will form a phenyl-substituted alkane.
5. Perform a series of reactions, such as hydrogenation and elimination, to adjust the carbon chain length and introduce the double bond at the desired position, ultimately forming dec-5-ene.

Key Concepts

Electrophilic Aromatic Substitution

Electrophilic aromatic substitution (EAS) is a fundamental reaction in organic chemistry where an electrophile replaces a hydrogen atom on an aromatic ring. In the context of synthesizing compounds from bromobenzene, understanding EAS is crucial, as bromobenzene can undergo this reaction to introduce various substituents, which can then be further manipulated to form desired products like dec-5-ene.

Alkylation Reactions

Alkylation reactions involve the introduction of an alkyl group into a molecule, often through nucleophilic substitution or EAS. When synthesizing dec-5-ene, alkyl halides can be used to add carbon chains to the aromatic system or to create alkenes. Recognizing how to effectively use alkyl halides in these reactions is essential for constructing the target compound.

Elimination Reactions

Elimination reactions are processes where two atoms or groups are removed from a molecule, resulting in the formation of a double bond. In the synthesis of dec-5-ene, elimination reactions can be employed after alkylation to generate the alkene from a saturated precursor. Understanding the conditions and mechanisms of elimination is vital for achieving the desired unsaturation in the final product.