This comprehensive set of practice problems on Stereochemistry includes questions on determining R and S configuration, R and S configuration in Fischer and Newman projections, and determining the relationship between molecules such as enantiomers, diastereomers, and constitutional isomers. There are … Read more
Let’s determine the relationship between the molecules in each of the following two pairs of molecules: They have the same chemical formula and connectivity of atoms, which, however, have different spatial arrangements. Therefore, they are stereoisomers: … Read more
To understand what configurational isomers are, let’s define/describe the terms “configuration” and “conformation”. Configuration is the orientation/direction of the atoms that we cannot change, whereas conformation is the orientation of the atoms which we can change via rotation about a … Read more
Enantiomers and diastereomers are types of stereoisomers. Recall that stereoisomers are isomers with the same connectivity but different spatial arrangement of atoms. The isomers with different connectivity of atoms are called constitutional isomers: The (R)-2-chlorobutane and (S)-2-chlorobutane shown … Read more
You might have heard the term “Nonsuperimposable Mirror Images” during the lecture but did not quite understand what it was and how it was related to enantiomers, diastereomers, or other types of correlations between organic molecules. So, what does … Read more
In the previous post, we talked about optical rotation which is caused by chiral compounds when plane-polarized light passes through their samples. An interesting feature about optical rotation was the discovery that enantiomers rotate the plane-polarized light to an equal … Read more
In the previous post, we talked about the optical activity and the observed rotation. Remember, the observed rotation is the degree and direction to which the plane of a polarized light rotates when passing through a sample of a chiral … Read more
In this post, we will learn how to determine eh absolute configuration of allenes. We are, of course, talking about chiral allenes like, for example, this one: Chirality of Allenes In order for the allene to be chiral, … Read more
Erythro and threo are common terms in stereochemistry used for naming molecules with two stereogenic centers. The names derive from the saccharides erythrose and threose, so let’s draw their Fischer projection to understand the basis of this notation: … Read more
To determine the R and S configuration of a chiral carbon in Newman projections, we need to look through the bond such that the lowest priority group is pointing back. But first, one question – why would anyone need to … Read more
