For the molecules shown,
(i) count the number of stereocenters present and
(ii) draw all possible stereoisomers.
(iii) Identify the relationships between stereoisomers as enantiomers or diastereomers.
(a)

Verified step by step guidance

1. Step 1: Identify stereocenters in the molecule. A stereocenter is typically a carbon atom bonded to four different groups. Examine each carbon atom in the molecule and determine if it meets this criterion.
2. Step 2: Count the total number of stereocenters. Once all stereocenters are identified, count them to determine the total number present in the molecule.
3. Step 3: Calculate the maximum number of stereoisomers. Use the formula 2^n, where 'n' is the number of stereocenters, to determine the maximum number of possible stereoisomers for the molecule.
4. Step 4: Draw all possible stereoisomers. For each stereocenter, assign configurations (R or S) systematically to generate all combinations of stereoisomers. Ensure that you represent each stereoisomer with its correct 3D structure (e.g., using wedge and dash bonds).
5. Step 5: Identify relationships between stereoisomers. Compare the stereoisomers to determine if they are enantiomers (non-superimposable mirror images) or diastereomers (stereoisomers that are not mirror images). Use the configurations (R/S) to help classify these relationships.

Key Concepts

Stereocenters

A stereocenter, or chiral center, is a carbon atom that is bonded to four different substituents, leading to non-superimposable mirror images known as enantiomers. The presence of stereocenters in a molecule is crucial for determining its stereochemistry and the number of possible stereoisomers. Each stereocenter can exist in two configurations, contributing to the overall stereoisomer count.

Stereoisomers

Stereoisomers are compounds that have the same molecular formula and connectivity of atoms but differ in the spatial arrangement of their atoms. They can be classified into two main types: enantiomers, which are non-superimposable mirror images, and diastereomers, which are not mirror images of each other. The number of stereoisomers for a molecule can be calculated using the formula 2^n, where n is the number of stereocenters.

Enantiomers and Diastereomers

Enantiomers are pairs of stereoisomers that are mirror images of each other, possessing opposite configurations at all stereocenters. In contrast, diastereomers differ in configuration at one or more stereocenters but not all, making them non-mirror images. Understanding these relationships is essential for predicting the behavior of molecules in chemical reactions and their interactions in biological systems.