Which of the following compounds has a stereoisomer that is a meso compound?

• A. $2,3-\text{dimethylpentane}$
• B. $2,3-\text{dibromobutane}$
• C. $3-\text{bromopentane}$
• D. $2-\text{bromobutane}$

Answer: (B)

Verified step by step guidance

1. Identify the stereocenters in each compound. A stereocenter (chiral center) is a carbon atom bonded to four different groups. For example, in 2,3-dibromobutane, carbons 2 and 3 are likely stereocenters because they each have a bromine substituent and different alkyl groups attached.
2. Determine if the compound can have stereoisomers by considering the number of stereocenters. The maximum number of stereoisomers is given by \$2^n\(, where \)n$ is the number of stereocenters.
3. Check for the presence of an internal plane of symmetry in any stereoisomer. A meso compound is achiral despite having stereocenters because it has a plane of symmetry that makes it superimposable on its mirror image.
4. For each compound, draw the possible stereoisomers and look for one that has a plane of symmetry. For example, in 2,3-dibromobutane, the meso form occurs when the two stereocenters have opposite configurations (R,S or S,R), creating a symmetrical molecule.
5. Conclude which compound has a stereoisomer that is meso by confirming the presence of such a symmetrical stereoisomer. In this case, 2,3-dibromobutane has a meso form, while the others do not because they lack the necessary stereocenters or symmetry.