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Ch.3 - Structure and Stereochemistry of Alkanes
Wade - Organic Chemistry 9th Edition
Wade9th EditionOrganic ChemistryISBN: 9780135213728Not the one you use?Change textbook
All textbooksWade 9th EditionCh.3 - Structure and Stereochemistry of AlkanesProblem 11a
Chapter 3, Problem 11a

Draw Newman projections of the following molecules viewed from the direction of the blue arrows.
(a)

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1
Identify the carbon-carbon bond that the blue arrow is pointing towards. This will be the axis of rotation for your Newman projection.
Determine the groups attached to the front carbon (the carbon closest to the viewer) and the back carbon (the carbon furthest from the viewer).
Draw a circle to represent the back carbon. The front carbon is represented by a dot in the center of the circle.
Arrange the substituents around the front carbon as three lines radiating from the center dot. These lines should be spaced 120 degrees apart.
Arrange the substituents around the back carbon as three lines radiating from the circle. These lines should also be spaced 120 degrees apart, but staggered relative to the front carbon's substituents.

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Key Concepts

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

Newman Projection

A Newman projection is a way of drawing a molecule to show the conformation of a carbon-carbon bond. It is viewed along the axis of the bond, with the front carbon represented by a dot and the back carbon by a circle. This projection helps visualize the spatial arrangement of substituents around the bond, which is crucial for understanding steric interactions and conformational isomerism.
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Introduction to Drawing Newman Projections

Conformational Isomerism

Conformational isomerism refers to the different spatial arrangements of atoms that result from rotation around a single bond. These isomers, also known as conformers, can interconvert through simple rotations. Understanding conformational isomerism is essential for analyzing the stability and reactivity of molecules, as different conformations can have significantly different energies and properties.
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Understanding what a conformer is.

Steric Hindrance

Steric hindrance occurs when atoms or groups within a molecule are positioned such that they physically impede each other's space, leading to increased energy and decreased stability. In Newman projections, steric hindrance is often visualized by the proximity of substituents on adjacent carbons. Recognizing steric hindrance is important for predicting the most stable conformations and understanding reaction mechanisms.
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Related Practice
Textbook Question

Draw Newman projections of the following molecules viewed from the direction of the blue arrows.

(b)

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Textbook Question

List each set of compounds in order of increasing boiling point.

b. Octane, (CH3)3C—C(CH3)3 and CH3CH2C(CH3)2CH2CH2CH3

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Textbook Question

List each set of compounds in order of increasing boiling point.

a. hexane, octane, and decane

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Textbook Question

Draw a graph, similar to Figure 3-9, of the torsional strain of 2-methylpropane as it rotates about the bond between C1 and C2. Show the dihedral angle and draw a Newman projection for each staggered and eclipsed conformation.

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Textbook Question

Without looking at the structures, give molecular formulas for the compounds: (a) 4-(1,1-dimethylethyl)octane and (b) 5-(1,2,2-trimethylpropyl)nonane. Use the names of the groups to determine the number of carbon atoms; then use the (2n + 2) rule.

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Textbook Question

Draw Newman projections of the following molecules viewed from the direction of the blue arrows.

(c)

2
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