Question

Which of the following Grignard Reagent will be used to prepare cyclohexylmethanol when treated with methanal?

• A. A
• B. B
• C. C
• D. D

Hint:

Grignard + Methanal \(\rightarrow\) \( 1^\circ \) Alcohol.
Grignard + other Aldehydes \(\rightarrow\) \( 2^\circ \) Alcohol.
Grignard + Ketones \(\rightarrow\) \( 3^\circ \) Alcohol.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Reaction of a Grignard reagent (\( R-MgX \)) with methanal (\( HCHO \)) followed by acid hydrolysis always yields a primary alcohol with one extra carbon atom (\( R-CH_2OH \)).
Step 2: Detailed Explanation:
The target product is cyclohexylmethanol, which has the structure: (Cyclohexyl ring)\( -CH_2OH \).
From the general reaction, the \( -CH_2OH \) part comes from the methanal (\( HCHO \)).
The \( R \) group must therefore be the cyclohexyl group.
Thus, the Grignard reagent required is Cyclohexylmagnesium bromide.
Step 3: Final Answer:
The correct reagent is Cyclohexylmagnesium bromide.