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Ch. 3 - Alkanes and Cycloalkanes: Properties and Conformational Analysis
Mullins - Organic Chemistry: A Learner Centered Approach 1st Edition
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Not the one you use?Change textbook
All textbooksMullins 1st EditionCh. 3 - Alkanes and Cycloalkanes: Properties and Conformational AnalysisProblem 58a
Chapter 2, Problem 58a

What is the mistake that was made in drawing each of the flipped chairs on the right from the chair on the left? [In these, assume that the angle through which you view the chair conformations doesn't change.]
(a) Diagram comparing chair conformations, highlighting mistakes in flipped chair drawings with numbered positions.

Verified step by step guidance
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Step 1: Understand the concept of chair conformations in cyclohexane. Cyclohexane can adopt a chair conformation to minimize steric strain and torsional strain. When flipping a chair conformation, axial substituents become equatorial, and equatorial substituents become axial, but their relative positions (up or down) remain unchanged.
Step 2: Analyze the chair conformation on the left. Identify the positions of substituents (axial or equatorial) and their orientation (up or down). This will serve as the reference for comparison with the flipped chairs on the right.
Step 3: Examine the flipped chairs on the right. Check whether the axial substituents have correctly switched to equatorial positions and vice versa. Ensure that the 'up' and 'down' orientations of substituents remain consistent during the flip.
Step 4: Identify any mistakes in the flipped chairs. Common errors include flipping substituents incorrectly (e.g., changing 'up' to 'down' or failing to switch axial to equatorial), or misrepresenting the overall geometry of the chair conformation.
Step 5: Summarize the specific mistake(s) made in each flipped chair. For example, if a substituent that was axial and 'up' in the original chair is incorrectly drawn as equatorial and 'down' in the flipped chair, highlight this error and explain why it violates the rules of chair flipping.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Chair Conformation

The chair conformation is a three-dimensional representation of cyclohexane that minimizes steric strain and torsional strain. It allows for the most stable arrangement of hydrogen atoms and substituents around the carbon atoms in the ring. Understanding this conformation is crucial for analyzing the stability and reactivity of cyclohexane derivatives.
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Understanding what a conformer is.

Flipping the Chair

Flipping the chair refers to the process of interconverting between two chair conformations of cyclohexane. This involves a transition where axial substituents become equatorial and vice versa. Recognizing the correct orientation of substituents after a flip is essential for accurately depicting the molecular structure and understanding its implications on stability.
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The 3 important factors when drawing chairs

Axial and Equatorial Positions

In chair conformations, substituents can occupy axial or equatorial positions. Axial substituents are oriented parallel to the axis of the ring, while equatorial substituents extend outward, minimizing steric hindrance. The distinction between these positions is vital for predicting the stability of different conformations and understanding the effects of substituent size and interactions.
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Related Practice
Textbook Question

For each chair on the left, place the substituents on the flipped chair. [Recall that the axial/equatorial designation changes from one chair to the next, but the carbon to which the substituent is attached does not.]

(c)

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Textbook Question

For each pair of conformations shown, choose which is most stable. If both are equally stable, then write 'no difference.' [If both conformations have the same number of axial substituents, choose the one with the smallest axial substituents.]

(e)

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Textbook Question

For each chair on the left, place the substituents on the flipped chair. [Recall that the axial/equatorial designation changes from one chair to the next, but the carbon to which the substituent is attached does not.]

(f)

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Textbook Question

For each pair of conformations shown, choose which is most stable. If both are equally stable, then write 'no difference.' [If both conformations have the same number of axial substituents, choose the one with the smallest axial substituents.]

(g)

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Textbook Question

For each chair on the left, place the substituents on the flipped chair. [Recall that the axial/equatorial designation changes from one chair to the next, but the carbon to which the substituent is attached does not.]

(e)

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Textbook Question

For each structure shown, draw the two chair conformations and choose which is most stable. Be sure that your second chair is the flipped version of the first. [Make sure that wedged substituents are up in the chair, regardless of whether up is equatorial or axial.]

(e)

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