Atropisomers - Online Tutor, Practice Problems & Exam Prep

Meso compounds, by actual definition, are achiral compounds having chiral diastereomers. However, for our convenience, we think of them as achiral compounds with chiral atoms (stereocenters). This definition makes it easy to identify meso compounds without us having to draw all possible chiral diastereomers. Determine how cis-cycloheptene is a meso compound under the actual definition, but not under the definition that we made for our own convenience.

Draw the three-dimensional structure of the following compound. Does it have asymmetric carbon atom(s)? If it does not have any asymmetric carbons, is it still chiral?

Each chiral center in a meso compound will always have opposing absolute configurations. As a result, a meso compound will always have an (R,S) or (S,R) configuration but never an (R,R) or (S,S). Why?

Identify whether a meso compound is a possible stereoisomer of the following compounds.

a. 2,4-dibromopentane

b. 1,3-dibromocyclopentane

Identify whether a meso compound is a possible stereoisomer of the following compounds.

a. hexane-2,4-diol

b. heptane-2,6-diol

Identify whether each of the following compounds has one or more achiral stereoisomers.

a. butane-2,3-diol

b. pentane-2,3-diol

Classify the following compounds as chiral or achiral.

a. (2S,3S)-2-bromo-3-chloropentane
b. (3R,4S)-3,4-dichlorohexane

Try to keep your drawing as symmetric as possible and mark any stereocenters with an asterisk (*). Indicate if a compound is meso. You can draw Fischer projections if that's preferable.

From the following molecules, determine the meso compound/s.

From the following molecules, pick which is/are meso compound/s.

From the given compounds, which one is meso?

For the structure below: 

i) Encircle the chiral centers. 

ii) Label each chiral carbon as (R) or (S). 

iii) Draw the internal plane of symmetry, if applicable. 

iv) Classify as chiral or achiral. 

v) Identify if it is a meso compound.