Dess-Martin oxidation

What is Dess-Martin oxidation?

The Dess-Martin oxidation is a chemical reaction that allows for the synthesis of compounds containing a carbonyl group. This reaction is named after the American chemists David Dess and Brian Martin, who first described it in 1983.

Dess-Martin oxidation
Dess-Martin oxidation

The Dess-Martin oxidation involves the oxidation of a compound called a “secondary alcohol” to a compound containing a carbonyl group, by means of a hypervalent iodine compound (for example: 12-I-5 triacetoxyperiodinane). The reaction is typically carried out in the presence of a base, such as sodium hydroxide, and a solvent, such as ethanol..

The hypervalent iodine compound is called the Dess-Martin periodinane (DMP), Dess-Martin reagent, Dess-Martin Periodinane reagent, or Dess-Martin oxidant, which tolerates a variety of functional groups.

The reaction proceeds in mild conditions and normally it takes 2h at room temperature in a solvent with either slightly acidic or neutral pH. The reaction gives high yields without overoxidation and can be easily worked up. Therefore, Dess-Martin oxidation is suitable for substrates containing sensitive functional groups. The reaction has been carried out in different solvents but often in dichloromethane or chloroform.

One of the advantages of the Dess-Martin oxidation is its high yield and efficiency. It is a relatively simple reaction that can be carried out under mild conditions and does not require the use of expensive or specialized reagents. In addition, the Dess-Martin oxidation is highly selective, meaning that it can produce compounds containing a carbonyl group with a high degree of control over the relative position of the substituents on the carbonyl group..

The Dess-Martin oxidation has a wide range of applications in the synthesis of pharmaceuticals, fragrances, and other chemicals. It has also been used in the synthesis of natural products, such as flavonoids and terpenoids..

Summary

The Dess-Martin oxidation is a valuable tool for the synthesis of compounds containing a carbonyl group and has proven to be a reliable and efficient method for the production of these compounds..

Example

An example of the Dess-Martin oxidation is the treatment of 2-propanol with Dess-Martin reagent (periodinane) in the presence of a base (such as sodium hydroxide) yields acetone as the product..

Overall reaction:
2-propanol + Dess-Martin reagent –> Acetone

In this example, 2-propanol acts as a secondary alcohol, and the Dess-Martin reagent is a combination of periodinane and a base (such as sodium hydroxide). The reaction proceeds via a series of oxidation and elimination steps to give the final product..

It is important to note that the Dess-Martin oxidation is a highly selective oxidation reaction, and it can be used to oxidize a wide range of alcohols with high efficiency and low toxicity. However, the Dess-Martin reagent is relatively expensive and relatively difficult to prepare..

Mechanism of reaction

The Dess-Martin oxidation reaction mechanism involves several steps:

Dess-Martin oxidation
Reaction mechanism of Dess-Martin oxidation
  • The first step is the formation of a complex between the Dess-Martin reagent (periodinane) and the alcohol substrate. This complex is formed by the nucleophilic attack of the oxygen atom of the alcohol on the electrophilic iodine atom of the periodinane..
  • Next, the periodinane-alcohol complex undergoes an oxidation reaction, which results in the formation of a periodinane-aldehyde or periodinane-ketone complex, depending on whether the alcohol substrate is primary or secondary..
  • In the third step, the complex undergoes an elimination reaction, which results in the formation of the aldehyde or ketone product. The elimination is facilitated by the basic nature of the reagent, typically sodium hydroxide.
    Lastly, the periodinane reagent is recycled by reducing it with a reducing agent such as sodium borohydride..

Overall, the Dess-Martin oxidation reaction mechanism can be summarized as:

  • complex formation
  • oxidation
  • elimination
  • recycling

It is important to note that the Dess-Martin oxidation is a highly selective oxidation reaction, and it can be used to oxidize a wide range of alcohols with high efficiency and low toxicity. However, the Dess-Martin reagent is relatively expensive and relatively difficult to prepare..

References

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