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🥼organic chemistry review

Terminal Alkene

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

Definition

A terminal alkene is an alkene (a molecule containing a carbon-carbon double bond) in which the double bond is located at the end of the carbon chain. These types of alkenes are important intermediates in the preparation of alcohols, as they can be converted to alcohols through various reactions.

5 Must Know Facts For Your Next Test

  1. Terminal alkenes can be converted to alcohols through the process of hydration, where a water molecule is added across the double bond.
  2. The hydration of terminal alkenes is a key step in the preparation of alcohols, as it allows for the introduction of the hydroxyl group.
  3. Terminal alkenes can also be converted to alcohols through other reactions, such as the addition of hydrogen (hydrogenation) or the addition of halogens (halogenation) followed by hydrolysis.
  4. The position of the double bond in a terminal alkene is important, as it determines the regiochemistry of the resulting alcohol product.
  5. Terminal alkenes are commonly used as building blocks in organic synthesis due to their reactivity and the ease with which they can be converted to other functional groups.

Review Questions

  • Explain the role of terminal alkenes in the preparation of alcohols.
    • Terminal alkenes are important intermediates in the preparation of alcohols. They can be converted to alcohols through the process of hydration, where a water molecule is added across the double bond. This reaction introduces the hydroxyl (-OH) group, which is the defining feature of alcohols. The position of the double bond in a terminal alkene is crucial, as it determines the regiochemistry of the resulting alcohol product. Terminal alkenes are commonly used as building blocks in organic synthesis due to their reactivity and the ease with which they can be converted to other functional groups.
  • Describe the different reactions that can be used to convert terminal alkenes to alcohols.
    • In addition to hydration, terminal alkenes can be converted to alcohols through other reactions. One method is the addition of hydrogen (hydrogenation), where the double bond is reduced to a single bond, forming an alkane with a hydroxyl group. Another approach is the addition of halogens (halogenation) followed by hydrolysis, where the halogen is replaced with a hydroxyl group. These alternative reactions, along with hydration, provide various pathways for the preparation of alcohols from terminal alkene starting materials. The choice of reaction depends on the specific requirements of the synthesis and the desired regiochemistry of the final alcohol product.
  • Analyze the importance of the position of the double bond in a terminal alkene for the preparation of alcohols.
    • The position of the double bond in a terminal alkene is crucial for the preparation of alcohols, as it determines the regiochemistry of the resulting alcohol product. When a terminal alkene undergoes hydration, the water molecule is added across the double bond, with the hydroxyl group being introduced at the carbon atom adjacent to the double bond. This means that the position of the double bond in the starting material directly influences the location of the hydroxyl group in the final alcohol. Understanding and controlling the regiochemistry of these reactions is essential for the targeted synthesis of specific alcohol products, which are widely used in organic chemistry and various industries.