Ch.5 - Stereochemistry

Wade9th EditionOrganic ChemistryISBN: 9780135213728Not the one you use?Change textbook

Wade 9th Edition

Ch.5 - Stereochemistry

Problem 15g

Chapter 5, Problem 15g

Draw three-dimensional representations of the following compounds. Which have asymmetric carbon atoms? Which have no asymmetric carbons but are chiral anyway? Use your models for parts (a) through (d) and any others that seem unclear.
(g)

Verified step by step guidance

Step 1: Analyze the given structure. The compound consists of two benzene rings fused together, forming a biphenyl system. The substituents on the biphenyl are two deuterium atoms (D) and two hydrogen atoms (H) attached to the ortho positions of each benzene ring.

Step 2: Determine the presence of asymmetric carbon atoms. An asymmetric carbon atom is a carbon bonded to four different groups. In this structure, there are no carbon atoms bonded to four distinct groups, so there are no asymmetric carbons.

Step 3: Evaluate chirality. A molecule is chiral if it is non-superimposable on its mirror image. In this case, the biphenyl system can be chiral due to restricted rotation around the single bond connecting the two benzene rings, provided the substituents (D and H) create a non-superimposable arrangement.

Step 4: Consider the spatial arrangement of the substituents. The bulky nature of the benzene rings and the substituents (D and H) prevent free rotation, locking the molecule into a specific three-dimensional configuration. This can result in chirality even without asymmetric carbons.

Step 5: Use molecular models to visualize the three-dimensional structure. Construct a model of the compound to confirm that the arrangement of substituents leads to chirality. Verify that the molecule is non-superimposable on its mirror image, confirming its chiral nature despite lacking asymmetric carbons.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

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

Asymmetric Carbon Atoms

Asymmetric carbon atoms, or chiral centers, are carbon atoms that are bonded to four different substituents. This unique arrangement allows for the existence of non-superimposable mirror images, known as enantiomers. Identifying these centers is crucial for determining the chirality of a compound, which can significantly influence its chemical behavior and interactions.

Chirality

Chirality refers to the geometric property of a molecule that makes it non-superimposable on its mirror image. A molecule can be chiral even without asymmetric carbon atoms if it has other elements of symmetry that create distinct spatial arrangements. This concept is essential in organic chemistry, particularly in the study of stereochemistry and the behavior of molecules in biological systems.

Three-Dimensional Representations

Three-dimensional representations of molecules, such as ball-and-stick models or space-filling models, provide a visual understanding of molecular geometry and spatial orientation. These models help in identifying chiral centers and understanding the overall shape of the molecule, which is critical for predicting reactivity and interactions in chemical reactions.

Recommended video:

Guided course

05:09

Representations of L-Configuration

Related Practice

Textbook Question

For each set of examples, make a model of the first structure, and indicate the relationship of each of the other structures to the first structure. Examples of relationships: same compound, enantiomer, structural isomer.

(a)

views

Textbook Question

Draw three-dimensional representations of the following compounds. Which have asymmetric carbon atoms? Which have no asymmetric carbons but are chiral anyway? Use your models for parts (a) through (d) and any others that seem unclear.

(c)

(d)

views

Textbook Question

(e)

(f)

(c)

Draw a Fischer projection for each compound. Remember that the cross represents an asymmetric carbon atom, and the carbon chain should be along the vertical, with the IUPAC numbering from top to bottom.

(a) (S)-propane-1,2-diol

(b) (R)-2-bromobutan-1-ol

views

Textbook Question

(a)

(b)

views

Draw three-dimensional representations of the following compounds. Which have asymmetric carbon atoms? Which have no asymmetric carbons but are chiral anyway? Use your models for parts (a) through (d) and any others that seem unclear.(g)

Verified video answer for a similar problem:

Key Concepts

Asymmetric Carbon Atoms

Chirality

Three-Dimensional Representations

Draw three-dimensional representations of the following compounds. Which have asymmetric carbon atoms? Which have no asymmetric carbons but are chiral anyway? Use your models for parts (a) through (d) and any others that seem unclear.
(g)