Question

The reagent used in the conversion of alcohol into aldehyde is:

• A. $LiAlH_4$
• B. PCC
• C. $NaBH_4$
• D. Grignard reagent

Hint:

Think of PCC as a "controlled" stop. It stops the oxidation at the Aldehyde stage. Stronger reagents like Jones Reagent ($CrO_3/H_2SO_4$) are like an express train—they go all the way to the Carboxylic Acid!

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The conversion of a primary alcohol (\(R-CH_2OH\)) to an aldehyde (\(R-CHO\)) is a process of controlled oxidation.
Step 2: Detailed Explanation:
1. \(LiAlH_4\) and \(NaBH_4\): These are strong and mild reducing agents, respectively. They would convert an aldehyde back to an alcohol.
2. Grignard reagent (\(RMgX\)): This is a nucleophilic reagent used to create new \(C-C\) bonds, typically reacting with carbonyl compounds to form alcohols.
3. PCC (Pyridinium chlorochromate): This is a mild and selective oxidizing agent. It oxidizes primary alcohols to aldehydes and stops the reaction there. Stronger oxidizers like \(KMnO_4\) would oxidize the aldehyde further to a carboxylic acid.
Step 3: Final Answer:
\(PCC\) is the appropriate reagent for this specific conversion.