Question

IUPAC name of \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{C}-\mathrm{CH}=\mathrm{CH}_{2}\) is (1) \(3,3,3\) -Trimethyl-1-propene (2) \(1,1,1\) -Trimethyl-2-butene (3) 3,3 -dimethyl- 1 -butene (4) 2,2 -dimethy \(1-3\) -butene

Short answer

Option (1), 3,3,3-Trimethyl-1-butene.

Step-by-step solution

Identify the parent chain

Find the longest continuous chain of carbon atoms that includes the double bond. In \(\left(\mathrm{CH}_{3}\right)_{3}\mathrm{C}-\mathrm{CH}=\mathrm{CH}_{2}\), the longest chain with the double bond is four carbons long, making it a butene.

Number the carbon atoms

Number the carbon atoms in the parent chain starting from the end closest to the double bond. This gives: \(1: \mathrm{CH}_{2}, 2: \mathrm{CH}=, 3: \mathrm{C}(-\mathrm{CH}_3) - ,4: \mathrm{C}(-\mathrm{CH}_3)(-\mathrm{CH}_3)\).

Identify and name substituents

Identify the substituents attached to the main chain. Here, there are three methyl groups (\(\mathrm{CH}_3\)) attached to carbon 3. These substituents are named 'trimethyl'.

Combine the names

Combine the number of the carbon where the substituents are located, the name of the substituents, and the name of the parent chain with its position of double bond. The name is thus 3,3,3-trimethyl-1-butene.

Match with provided options

Compare the derived IUPAC name with the given options. The correct name is 3,3,3-trimethyl-1-butene, which matches option (1).

Key concepts

Organic Chemistry

Organic chemistry is the branch of chemistry that deals with the study of carbon-containing compounds and their properties. It's a vast field because carbon atoms can form stable bonds with many other elements, leading to a plethora of different molecules. In organic chemistry, the naming of compounds, like the one in our exercise, follows specific rules set by the International Union of Pure and Applied Chemistry (IUPAC). This system ensures that each compound has a unique and systematic name. Understanding the basics of organic chemistry will help you recognize patterns, predict reactivity, and understand the structure of various molecules.

Hydrocarbons

Hydrocarbons are the simplest organic compounds, consisting only of carbon (C) and hydrogen (H) atoms. They are categorized into alkanes, alkenes, alkynes, and aromatic hydrocarbons based on the types of bonds and the structure of the molecule.

• Alkanes: These have single bonds between carbon atoms (e.g., methane, ethane).
• Alkenes: These have at least one double bond between carbon atoms (e.g., ethene, propene).
• Alkynes: These have at least one triple bond between carbon atoms (e.g., ethyne, propyne).
• Aromatic hydrocarbons: These contain benzene rings (e.g., benzene, toluene).

The compound in the exercise, \(\text{(CH}_{3}\text{)}_{3}\text{C}-\text{CH}=\text{CH}_{2}\), is an alkene due to the presence of the double bond.

Double Bonds

Double bonds are a key feature in many organic molecules, particularly alkenes. A double bond consists of one sigma (σ) bond and one pi (π) bond and is generally more reactive than single bonds.

Here are a few characteristics of double bonds:

• They restrict the rotation around the bond, giving rise to different spatial arrangements of atoms, known as isomers.
• They have an electron-rich region that can participate in chemical reactions such as addition reactions.
• In IUPAC nomenclature, the double bond position is indicated by the lowest numbered carbon atom involved in the double bond.

In our compound \(\text{(CH}_{3}\text{)}_{3}\text{C}-\text{CH}=\text{CH}_{2}\), the double bond starts from the second carbon atom in the chain, making it a butene.

Structural Isomerism

Structural isomerism occurs when compounds have the same molecular formula but different structures. This can significantly affect the chemical and physical properties of the molecules. There are several types of structural isomerism:

• Chain isomerism: Different arrangements of the carbon chain.
• Position isomerism: Functional groups attached at different positions on the same carbon chain.
• Functional group isomerism: Different functional groups.

The compound in the exercise can be a good example to understand position isomerism, as changing the position of the double bond or substituents can lead to different isomers. For example, moving the double bond to a different carbon in the chain can create another compound with its own unique properties and name. In this solution, we focused on identifying the correct structure and naming it correctly according to the position of the double bond and substituents.