Profile
Settings
Refer your friends
Sign out
In the presence of a proton source, the Pfitzner–Moffatt oxidation transforms primary and secondary alcohols into their respective aldehydes and ketones under mild and nearly neutral conditions. This reaction uses dimethyl sulfoxide (DMSO) and dicyclohexylcarbodiimide (DCC) as the proton source and is known as the Pfitzner–Moffatt reagent. Primary and secondary hydroxyl groups in a range of compounds have been observed to be amenable to this reaction. The oxidation of primary and secondary alcohols to produce their corresponding aldehydes and ketones is a common use of this reaction.
Moffatt-Pfitzner Oxidation
To convert primary or secondary alcohols to aldehydes or ketones, dimethyl sulfoxide-based oxidation can be used as it does not require heavy metal oxidants. Dicyclohexylcarbodiimide (DCC) is protonated and then sulfated by dimethyl sulfoxide to produce the activator. The alcohol oxygen is added to the sulphur atom of intermediate 2 by protonating it once more. Sulfenate salt and stable dicyclohexyl urea are produced.
The dihydrogen phosphate anion causes this species to decompose into the carbonyl molecule. Although phosphoric acid is a good acid catalyst for this reaction, hydrogen chloride, sulfuric acid, and trifluoroacetic acid are ineffective. This is not the case, however, with pyridinium trifluoroacetate. To complete the reaction, it is important that the acid’s conjugate base be basic enough.
Advantages and Disadvantages of the Reaction
The Pfitzner-Moffatt oxidation is a method for oxidising alcohols that makes use of DMSO, DCC, and Bronsted acid. Swern and Parikh-Doering reactions have more compact active species, whereas this reaction’s active species are bulkier. Taking advantage of the fact that this reaction is susceptible to steric influences, it is feasible to selectively oxidise hydroxyl groups that are less inhibited. Another advantage of this reaction is that it can be performed at room temperature. The elimination of the urea byproduct and the creation of competing methylthiomethyl ether byproducts are two of the reaction’s drawbacks.
Oxidation of Alcohols
Alcohols are a class of organic molecules in which the alkane of a single bond bears one, two, or more hydroxyl (-OH) groups. The common formula for these compounds is OH. Chemical transformations of alcohols into aldehydes and ketones are commonplace in organic chemistry, making them essential building blocks. Two types of reactions take place in alcohol. Both the R-O and O-H bonds are capable of being broken by these reactions.
Oxidation transforms the alcohols into aldehydes and ketones. There are many important processes in the field of synthetic organic chemistry that involve oxidising ethanol to aldehydes and ketones. It is necessary to use the best oxidants for these conversions, which include high valent ruthenium, as catalysts for these reactions to occur. It is critical to be well-versed in oxidation reactions and the factors and mechanisms that influence them for the efficient production of these items.
The type of carbonyl substituents put on the carbonyl carbon affects the oxidation process of the alcohols. The carbonyl carbon must have an atom of hydrogen for the oxidation reaction to occur.
The main alcohols are oxidised to produce aldehydes. An oxidising agent, acidified potassium dichromate (VI) solution, can further convert the generated aldehyde to carboxylic acids. To put it another way, the overall effect is achieved when an acid or alkali removes the hydrogen from the hydroxyl (-OH) group of an alcohol as well as the carbon linked to it.
The oxidation of secondary alcohols is used to produce Ketones. The ketone termed propanone can be produced by applying the heat to secondary alcohol propan-2-ol with potassium dichromate (VI) or sodium solution that is acidified with weak sulphuric acid. To further oxidise the Ketones, the C–C bond would have to be broken, which would require too much energy.
Conclusion
Aldehydes and ketones can be formed from primary and secondary alcohols by the Pfitzner–Moffatt oxidation reaction, also known as the Moffatt oxidation. Dimethyl sulfoxide (DMSO) and dicyclohexylcarbodiimide are the oxidants (DCC). A wide range of primary and secondary alcohols can be converted to aldehydes and ketones using the Burgess reagent in the presence of dimethyl sulfoxide for high yields and under mild conditions. The wood industry produces DMSO as a byproduct. Because of its low cost, stability, and low toxicity, it is widely employed as a solvent in organic synthesis in the pharmaceutical industry.
