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]多项填空题
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Question

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]多项填空题

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我们收录了全球超50000道真实原题与详细解析,现在登录,立即获得答案。

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]多项填空题

类似问题

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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]多项填空题

类似问题

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

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})|]?

更多留学生实用工具

希望你的学习变得更简单

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