For the compound below:a. Give the IUPAC name (no stereochemical designation required. [1 mark]b. Draw the two possible chair conformers of the compound and use equilibrium arrows to show which form will predominate. Explain your selection. [4 marks][Fill in the blank]

Question

BlackTom AI · Accepted Answer

Numbering the ring gives substituents at adjacent carbons, so the correct substitutive name (alphabetical order) is 1-bromo-2-methylcyclohexane.

Relevant knowledge points:
- Cyclohexane adopts chair conformations; substituents can be axial or equatorial.
- Large/sterically demanding substituents prefer the equatorial position to minimize 1,3-diaxial (steric) interactions.
- A ring flip converts axial substituents to equatorial and vice versa; the more stable conformer is the one with the bulkier group equatorial.
- IUPAC substituent listing is alphabetical (bromo before methyl) and numbering gives lowest locants (1 and 2).

Step-by-step reasoning:
1. Identify substituents and positions from the structure: bromine and methyl on adjacent carbons → cyclohexane-1,2-disubstituted.
2. Apply IUPAC rules: give lowest locants and list substituents alphabetically → 1-bromo-2-methylcyclohexane.
3. Consider chair conformers: draw one chair with the methyl group equatorial at C2 and the bromine axial at C1. The ring-flipped conformer has methyl axial and bromine equatorial.
4. Compare stabilities: the equatorial methyl conformer is more stable because an equatorial methyl avoids the unfavorable 1,3-diaxial steric interactions that occur when methyl is axial (axial methyl experiences steric repulsion with the two axial hydrogens on the 1,3 positions). Although bromine is a relatively bulky atom, the methyl substituent produces larger 1,3-diaxial strain when axial, so the conformer with methyl equatorial is favored.
5. Show equilibrium arrows with the arrow pointing toward the conformer having methyl equatorial (major) and the conformer with methyl axial (minor).

Why the correct answer is correct:
- Naming: "1-bromo-2-methylcyclohexane" follows lowest locants and alphabetical order.
- Conformational preference: steric 1,3-diaxial interactions make axial methyl energetically costly; placing methyl equatorial minimizes strain, so that conformer predominates.

Why other possibilities are incorrect:
- Writing the name as 2-methyl-1-bromocyclohexane reverses alphabetical order (IUPAC lists substituents alphabetically), so it is not the preferred form.
- Claiming bromine must be equatorial as the major factor is incorrect here because methyl produces greater 1,3-diaxial destabilization when axial and thus dictates the preferred equatorially substituted conformer.

Conclusion: The IUPAC name is 1-bromo-2-methylcyclohexane. The more stable chair conformer has the methyl group equatorial and the bromine axial; the ring-flipped conformer has the methyl group axial. The equatorial methyl conformer predominates because it avoids unfavorable 1,3-diaxial interactions. This matches the provided answer.

For the compound below:a. Give the IUPAC name (no stereochemical designation required. [1 mark]b. Draw the two possible chair conformers of the compound and use equilibrium arrows to show which form will predominate. Explain your selection. [4 marks][Fill in the blank]Multiple fill-in-the-blank

Similar Questions

The lowest energy chair conformation of cis-1,3-dimethyl cyclohexane will have the methyl substituents:[Fill in the blank]

Match the following contents of the Australian Food Standards Code to the relevant section you would find them in. 1: Standards that apply to all foods 2: Standards for food safety 3: Standards that apply to specific foods/food categories 4: Standards for production of high-risk foods

The Australian Food Standards Code sets out numerical limits of different substances. Match the following limits to the type of substance of which the limit is for. 1: MPL 2: MRL 3: ML

Question textIdentify the names of the following points on a dose-response curve.Point A: Answer 1 Question 5[input]Point B: Answer 2 Question 5[input]Point C: Answer 3 Question 5[input]

True or false?It is mandatory for all food business in the world to follow the standards set in the Codex Alimentarius.

Which body is responsible for conducting compliance audits on food businesses in NSW?

Which of the following are categories of hazards? Select all that apply.

What is [math: |P(A×{1,2})|]?

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler