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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: 9780137566471당신이 사용하는 게 아니라요?교과서 변경
모든 교과서Mullins 1st EditionCh. 3 - Alkanes and Cycloalkanes: Properties and Conformational Analysis문제 55b
2장, 문제 55b

Looking down the indicated bond, show the three most stable conformations and choose the one that is most stable. Be sure that the first Newman projection you show is the one you see initially (before rotation). [Why should none of your three Newman projections show eclipsed conformations?]
(b) <IMAGE>

검증된 단계별 안내
1
Step 1: Understand the concept of Newman projections. Newman projections are a way to visualize the spatial arrangement of atoms around a single bond by looking directly down the axis of the bond. The conformations can be staggered or eclipsed, with staggered conformations generally being more stable due to minimized torsional strain.
Step 2: Identify the bond to be analyzed. In this problem, you are asked to look down the indicated bond. Carefully examine the molecule and locate the bond axis that you will use to create the Newman projection.
Step 3: Draw the initial Newman projection. Looking down the bond axis, represent the front carbon as a dot and the back carbon as a circle. Arrange the substituents on both carbons based on their positions in the molecule. Ensure this projection reflects the molecule before any rotation.
Step 4: Rotate the back carbon in increments of 120° to generate the three staggered conformations. For each rotation, redraw the Newman projection, ensuring that the substituents on the front and back carbons are correctly positioned. Avoid eclipsed conformations, as they are less stable due to torsional strain.
Step 5: Compare the three staggered conformations to determine the most stable one. Stability is influenced by factors such as steric hindrance and the size of substituents. The conformation with the least steric hindrance and the most favorable interactions between substituents will be the most stable.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
2m

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Newman Projections

Newman projections are a way to visualize the conformation of a molecule by looking down a specific bond. This representation allows chemists to analyze the spatial arrangement of atoms or groups attached to the carbon atoms involved in the bond. By rotating around the bond, different conformations can be depicted, helping to identify stable and unstable arrangements.
추천 영상:
00:34
Introduction to Drawing Newman Projections

Conformational Stability

Conformational stability refers to the relative energy of different spatial arrangements of a molecule. In organic chemistry, staggered conformations are generally more stable than eclipsed ones due to reduced steric strain and torsional strain. Understanding the factors that contribute to stability, such as steric hindrance and torsional strain, is crucial for predicting the most favorable conformation.
추천 영상:
03:29
Understanding what a conformer is.

Eclipsed vs. Staggered Conformations

Eclipsed conformations occur when atoms or groups on adjacent carbons are aligned with each other, leading to increased steric repulsion and higher energy states. In contrast, staggered conformations have groups positioned at angles to each other, minimizing repulsion and resulting in lower energy states. The question emphasizes that none of the Newman projections should show eclipsed conformations because they are less stable and energetically unfavorable.
추천 영상:
03:29
Understanding what a conformer is.
관련 실천
교과서 질문

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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교과서 질문

Using the numbers shown in the chair conformation on the left, label the carbons of the flipped chair on the right. [Assume that the angle through which you view the chair conformation doesn't change.] 

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교과서 질문

Given the following structures, show the Newman projection that would result from looking down the indicated bond in the direction shown. [Orient yourself as if you were the eyeball looking down the bond. Some of the examples have been partially completed for you to fill in the rest.]

(l) <IMAGE>

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교과서 질문

For each pair of conformations shown, choose which is most stable. [If both conformations have the same number of gauche interactions, choose the one where the interactions are between smaller groups.]

(f)

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교과서 질문

For each pair of conformations shown, choose which is most stable. [If both conformations have the same number of gauche interactions, choose the one where the interactions are between smaller groups.]

(e)

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교과서 질문

Looking down the indicated bond, show the three most stable conformations and choose the one that is most stable. Be sure that the first Newman projection you show is the one you see initially (before rotation). [Why should none of your three Newman projections show eclipsed conformations?]

(e) <IMAGE>

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