Which of the following reactions will yield a meso product?

• A.
• B.
• C.
• D.

Answer: (D)

Verified step by step guidance

1. Identify the type of reaction for each given chemical equation. The first reaction involves mCPBA and an alkene, indicating an epoxidation reaction followed by acid-catalyzed ring opening.
2. The second reaction involves Br2 and an alkene, suggesting a halogenation reaction that typically results in anti-addition of bromine atoms across the double bond.
3. The third reaction involves mCPBA and an alkene, indicating an epoxidation reaction, which forms an epoxide across the double bond.
4. The fourth reaction involves OsO4 and an alkene, indicating a syn-dihydroxylation reaction, which adds two hydroxyl groups to the same side of the double bond.
5. To determine which reaction yields a meso product, consider the stereochemistry of the products. A meso compound is achiral despite having stereocenters, due to an internal plane of symmetry. The syn-dihydroxylation of a symmetrical alkene, such as cyclopentene, can yield a meso compound if the resulting diol has an internal plane of symmetry.