Using 1,2-dimethylcyclohexene as your starting material, show how you would synthesize the following compounds. (Once you have shown how to synthesize a compound, you may use it as the starting material in any later parts of this problem.) If a chiral product is shown, assume that it is part of a racemic mixture.

(c)

Verified step by step guidance

1. Step 1: Analyze the starting material, 1,2-dimethylcyclohexene. It is an alkene with a double bond between two carbons in the cyclohexane ring, and two methyl groups attached to the carbons involved in the double bond.
2. Step 2: Recognize the target product, which is a vicinal dibromide (two bromine atoms attached to adjacent carbons). This suggests the use of an anti-addition reaction mechanism.
3. Step 3: To achieve the transformation, use bromine (Br₂) in an inert solvent like CCl₄. Bromine reacts with the double bond in an anti-addition manner, forming a bromonium ion intermediate.
4. Step 4: The bromonium ion intermediate is attacked by a bromide ion (Br⁻) from the opposite side, leading to the anti-addition of bromine across the double bond. This results in the formation of the vicinal dibromide product.
5. Step 5: Since the product is chiral, the reaction produces a racemic mixture (equal amounts of both enantiomers) due to the planar nature of the double bond in the starting material.

Key Concepts

Electrophilic Addition Reactions

Electrophilic addition reactions are fundamental in organic chemistry, particularly for alkenes like 1,2-dimethylcyclohexene. In these reactions, an electrophile reacts with the double bond of the alkene, leading to the formation of a more saturated product. Understanding the mechanism of these reactions, including the formation of carbocations and the role of nucleophiles, is crucial for synthesizing various compounds from alkenes.

Stereochemistry

Stereochemistry involves the study of the spatial arrangement of atoms in molecules and how this affects their chemical behavior. In the context of synthesizing compounds from 1,2-dimethylcyclohexene, recognizing chiral centers and understanding concepts like enantiomers and diastereomers is essential. This knowledge is particularly important when dealing with racemic mixtures, as it influences the properties and reactivity of the synthesized products.

Functional Group Transformations

Functional group transformations are reactions that convert one functional group into another, which is a key aspect of organic synthesis. Starting from 1,2-dimethylcyclohexene, various transformations can be employed, such as oxidation, reduction, or substitution reactions, to create desired products. Mastery of these transformations allows chemists to design synthetic pathways effectively and achieve specific molecular architectures.