Question

Periodic acid oxidizes (a) 1,4 -diols (b) 1, 3-diols (c) 1,2 -diols (d) \(\beta\)-ketoaldehyde

Short answer

Periodic acid oxidizes 1,2-diols (option c).

Step-by-step solution

Understanding the Problem

First, we need to determine the function of periodic acid. Periodic acid (HIO4) is a chemical reagent that can oxidize 1,2-diols (vicinal diols), cleaving the bond between the two adjacent carbon atoms that both carry an OH group.

Identifying the Structure to be Cleaved

We should identify which of the given options have the structure of a 1,2-diol. - 1,4-diol has -OH groups on alternate carbon atoms and is not cleaved by periodic acid. - 1,3-diol has -OH groups separated by one carbon and is not susceptible. - 1,2-diol has adjacent -OH groups, making it a target for periodic acid oxidation. - β-ketoaldehyde does not fit the profile of a diol.

Determining the Reactive Option

Since periodic acid specifically cleaves 1,2-diols, which have adjacent OH groups, option (c) is the correct choice because it describes a 1,2-diol with the necessary structure for this reaction.

Key concepts

1,2-diols

A 1,2-diol is a type of molecular structure where two hydroxyl groups (-OH) are attached to adjacent carbon atoms in a carbon chain. This configuration is also commonly referred to as a vicinal diol. The term 'vicinal' arises from the Latin word 'vicinus', meaning 'neighboring', which perfectly describes the placement of the hydroxyl groups.

The particular placement of the -OH groups on adjacent carbons allows 1,2-diols to undergo specific chemical reactions that other types of diols cannot. One of these unique reactions involves their oxidation by periodic acid (HIO₄), a process which effectively cleaves the bond between the two carbon atoms bearing the hydroxyl groups. This cleavage is what distinguishes 1,2-diols in a variety of chemical contexts, making them highly relevant in synthetic and analytical chemistry.

Understanding 1,2-diols is essential for recognizing their behavior in reactions where such specific structural attributes are key. They serve as starting materials for a series of complex reactions and have roles in creating chain-shortened molecules due to the cleavage of the carbon-carbon bond in their structure.

vicinal diols

Vicinal diols are merely another name for 1,2-diols because they describe the same chemical structure: two hydroxyl groups on adjacent carbons. These diols play a pivotal role in many oxidative processes, which often form the basis of further chemical transformations.

When thinking about vicinal diols in terms of reactions, it is important to understand:

• The key role of having OH groups right next to each other.
• The susceptibility of these hydroxyl-bearing carbons to oxidative cleavage.
• The ability of periodic acid to target and cleave the C-C bond between adjacent carbons.

This susceptibility is due to the increased reactivity that the neighboring -OH groups contribute, making it possible for reagents like periodic acid to access and break the carbon framework efficiently.

The cleavage of vicinal diols is especially useful in understanding and identifying molecular structures or even breaking down larger biological molecules like sugars into simpler components. In a biological or synthetic context, this makes vicinal diols not just interesting, but highly functional.

cleaving carbon-carbon bond

Cleaving a carbon-carbon bond between vicinal diols involves breaking the covalent bond linking two carbon atoms, each of which has a hydroxyl group bound to it. This process is facilitated by periodic acid (HIO₄), allowing the molecule to split into smaller fragments.

Here's how the process works:

• Periodic acid oxidizes the vicinal diol.
• This oxidation results in the cleavage of the bond between the two carbon atoms.
• The -OH groups play a crucial role, since their proximity opens up the pathway for the selective cleavage reaction.

Such reactions are extremely valuable in organic chemistry because they provide a direct way to dissect complex molecules. By breaking carbon frameworks in a controlled fashion, chemists gain the ability to create simpler aldehydes and ketones from diols.

This kind of selective bond-breaking has numerous applications, including structural elucidation and synthesis pathways, especially in cases where a better understanding of molecule configuration and composition is required.