Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

5. Chirality

Chirality

Organic Chemistry

5. Chirality

Chirality

Previous problemNext problem

3:24 minutes

Problem 15a,b

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.
(a)
(b)

Verified step by step guidance

Step 1: Understand the problem. You are tasked with determining the three-dimensional structure of the given compounds, identifying asymmetric carbon atoms (if any), and determining whether the compounds are chiral even in the absence of asymmetric carbons. Chirality and asymmetry are key concepts here.

Step 2: Analyze compound (a) ClHC═C═CHCl (1,3-dichloropropadiene). Draw the structure of the compound, noting that it contains two double bonds in a conjugated system. The chlorine atoms are attached to the first and third carbons. Consider the spatial arrangement of the substituents around the double bonds, as double bonds restrict rotation.

Step 3: Determine if compound (a) has asymmetric carbons. An asymmetric carbon is a carbon atom bonded to four different groups. In this compound, all carbons are part of the double bonds, and none are bonded to four different groups. Therefore, there are no asymmetric carbons. Next, assess chirality. A molecule can be chiral without asymmetric carbons if it lacks a plane of symmetry and is non-superimposable on its mirror image. Evaluate the spatial arrangement of the substituents to determine chirality.

Step 4: Analyze compound (b) ClHC═C═CHCH3 (1-chlorobuta-1,2-diene). Draw the structure of the compound, noting that it contains two double bonds in an allene system. The chlorine atom is attached to the first carbon, and the methyl group is attached to the fourth carbon. Consider the unique geometry of allenes, where the two π-bonds are orthogonal to each other, creating a three-dimensional structure.

Step 5: Determine if compound (b) has asymmetric carbons. As with compound (a), check if any carbon is bonded to four different groups. In this case, none of the carbons meet this criterion. Next, assess chirality. Due to the orthogonal arrangement of the π-bonds in allenes, the substituents on the terminal carbons can create a chiral center even in the absence of asymmetric carbons. Evaluate the substituents to confirm chirality.

Verified video answer for a similar problem:

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

Video duration:

Play a video:

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 non-superimposable mirror images, known as enantiomers. Identifying these centers is crucial for determining the chirality of a compound, which affects its optical activity and reactivity.

Chirality Without Asymmetric Carbons

Some molecules can exhibit chirality even without asymmetric carbon atoms due to their geometric arrangement. This can occur in compounds with restricted rotation around double bonds or in cyclic structures, leading to non-superimposable mirror images. Understanding this concept is essential for recognizing chiral behavior in various organic compounds.

Three-Dimensional Molecular Representation

Three-dimensional representations of molecules, such as ball-and-stick models or space-filling models, help visualize the spatial arrangement of atoms. These models are vital for understanding molecular geometry, bond angles, and the overall shape of the molecule, which are important for predicting reactivity and interactions in organic chemistry.

Watch next

Master What is chirality? with a bite sized video explanation from Johnny

Start learning