Skip to main content
Chemistry LibreTexts

13.10: Deoxygenation of the Carbonyl Group

  • Page ID
    201232
  • \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

    Objectives

    After completing this section, you should be able to

    1. write an equation to illustrate the Wolff‑Kishner reduction of an aldehyde or ketone.
    2. identify the product formed from the Wolff‑Kishner reduction of a given aldehyde or ketone.
    Key Terms

    Make certain that you can define, and use in context, the key term below.

    • Wolff‑Kishner reduction
    Study Notes

    After studying this section, you can add yet another method of reducing organic compounds to your growing list of reduction reactions.

    Aldehydes and ketones can be converted to a hydrazine derivative by reaction with hydrazine. These "hydrazones" can be further converted to the corresponding alkane by reaction with base and heat. These two steps can be combined into one reaction called the Wolff-Kishner Reduction which represents a general method for converting aldehydes and ketones into alkanes. Typically a high boiling point solvent, such as ethylene glycol, is used to provide the high temperatures needed for this reaction to occur. Note! Nitrogen gas is produced as part of this reaction.

    Reaction of Aldehydes or Ketones with Hydrazine Produces a Hydrazone

    Reaction diagram. A ketone or aldehyde reacts with hydrazine to form hydrazone and water.

    Reaction with a Base and Heat Converts a Hydrazone to an Alkane

    Reaction diagram. Hydrazone reacts with potassium hydroxide and heat to form an alkane and nitrogen.

    Both Reactions Together Produces the Wolff-Kishner Reduction

    Reaction diagram. An aldehyde or ketone reacts with hydrazine, potassium hydroxide, and heat to form an alkane and nitrogen.

    Example

    Reaction diagram. Cyclopentanone reacts with hydrazine, potassium hydroxide and heat to form cyclopentane.

    Mechanism of the Wolff-Kishner Reduction

    1) Deprotonation of Nitrogen

    2) Protonation of the Carbon

    3) Deprotonation of Nitrogen

    4) Protonation of Carbon

    Exercise

    Exercise 19.9.1

    Please draw the products of the following reactions.

    problem 1 structures.png

    Answer

      answers 1 structures.svg

    Contributors and Attributions


    13.10: Deoxygenation of the Carbonyl Group is shared under a not declared license and was authored, remixed, and/or curated by LibreTexts.

    • Was this article helpful?