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🥼organic chemistry review

2,3-dibromobutane

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

2,3-dibromobutane is a chemical compound with the formula CH3CHBrCHBrCH3. It is a saturated hydrocarbon with two bromine atoms attached to the second and third carbon atoms of the four-carbon chain. This structural feature is important in the context of meso compounds, which are a type of stereoisomer.

5 Must Know Facts For Your Next Test

  1. 2,3-dibromobutane has two stereogenic centers, meaning it can exist as two pairs of enantiomers.
  2. One of the pairs of enantiomers is a meso compound, which has a plane of symmetry and is therefore achiral and optically inactive.
  3. The other pair of enantiomers are chiral and can rotate the plane of polarized light, making them optically active.
  4. Meso compounds are important in organic chemistry because they do not contribute to the optical activity of a mixture, even if other chiral compounds are present.
  5. The presence of the two bromine atoms on the 2,3-dibromobutane molecule makes it a useful model compound for understanding the concepts of stereoisomerism and meso compounds.

Review Questions

  • Explain how the structural features of 2,3-dibromobutane contribute to it being a meso compound.
    • The 2,3-dibromobutane molecule has two stereogenic centers, which means it can exist as a pair of enantiomers. However, due to the symmetry of the molecule, one of the pairs of enantiomers is a meso compound. A meso compound has a plane of symmetry, making it achiral and optically inactive. This is because the two stereogenic centers in 2,3-dibromobutane cancel out each other's optical activity, resulting in the meso form.
  • Describe the relationship between 2,3-dibromobutane and other stereoisomers, and how this is important in the context of meso compounds.
    • In addition to the meso form of 2,3-dibromobutane, the molecule can also exist as a pair of chiral enantiomers. Enantiomers are non-superimposable mirror images of each other and are optically active, meaning they can rotate the plane of polarized light. The presence of both meso and chiral forms of 2,3-dibromobutane highlights the importance of understanding stereoisomerism in the context of meso compounds. Meso compounds do not contribute to the overall optical activity of a mixture, even if other chiral compounds are present, which is a key concept in organic chemistry.
  • Analyze the significance of 2,3-dibromobutane as a model compound for studying the concepts of stereoisomerism and meso compounds, and how this knowledge can be applied to more complex organic molecules.
    • The 2,3-dibromobutane molecule serves as a valuable model compound for studying the principles of stereoisomerism and meso compounds in organic chemistry. By understanding the structural features and stereochemical properties of 2,3-dibromobutane, students can develop a deeper understanding of how the spatial arrangement of atoms can lead to the formation of different stereoisomers, including meso compounds. This knowledge can then be applied to more complex organic molecules, allowing students to predict and analyze the stereochemical characteristics of a wide range of organic compounds. The ability to recognize and differentiate between meso and chiral forms is crucial for understanding reaction mechanisms, predicting product distributions, and interpreting experimental data in organic synthesis and analysis.