Propose a synthesis of the carbonyl(s) using the (ii) dihydroxylation/periodic acid cleavage pathways.
(b)

Verified step by step guidance

1. Step 1: Begin by identifying the starting material that can undergo dihydroxylation. Typically, alkenes are suitable candidates for this transformation.
2. Step 2: Perform dihydroxylation on the alkene using a reagent such as osmium tetroxide (OsO₄) or potassium permanganate (KMnO₄) to convert the alkene into a vicinal diol. This step introduces two hydroxyl groups across the double bond.
3. Step 3: Once the vicinal diol is formed, the next step is to cleave the diol using periodic acid (HIO₄). Periodic acid selectively cleaves the C-C bond between the two hydroxyl groups, resulting in the formation of two carbonyl compounds.
4. Step 4: Analyze the structure of the resulting carbonyl compounds. Depending on the initial alkene structure, you may obtain aldehydes or ketones as products.
5. Step 5: Consider any additional steps or modifications needed to achieve the desired carbonyl compound, such as adjusting the alkene structure or using protective groups if necessary.

Key Concepts

Dihydroxylation

Dihydroxylation is a chemical reaction that involves the addition of two hydroxyl groups (OH) across a double bond in an alkene, resulting in a vicinal diol. This reaction can be achieved using reagents like osmium tetroxide (OsO4) or potassium permanganate (KMnO4). The process is stereospecific, typically yielding syn diols, where both hydroxyl groups add to the same side of the double bond.

Periodic Acid Cleavage

Periodic acid cleavage is a reaction where vicinal diols are cleaved by periodic acid (HIO4) to form two carbonyl compounds, such as aldehydes or ketones. This reaction is useful for breaking down complex molecules into simpler carbonyl fragments. The mechanism involves the formation of a cyclic periodate ester, which then decomposes to yield the carbonyl products.

Carbonyl Compounds

Carbonyl compounds are organic molecules that contain a carbon-oxygen double bond (C=O), such as aldehydes and ketones. They are highly reactive due to the polar nature of the carbonyl group, making them key intermediates in many organic synthesis pathways. Understanding their reactivity and the types of reactions they undergo is crucial for designing synthetic routes in organic chemistry.