Question

Identify the correct statement: (A) Nitriles react with Grignard Reagent followed by hydrolysis to give carbonyl compounds, (B) Aldehyde reacts with alcohol to form hemiacetal, (C) Carbonyl compounds are converted to corresponding acetal to increase chemoselectivity, (D) Carbonyl compound reacts with $2^{\circ}$ amines to form enamines.}

• A. A, B and C only
• B. A, C and D only
• C. B, C and D only
• D. A, B, C and D only

Hint:

Protection (Acetal) $\rightarrow$ Reaction $\rightarrow$ Deprotection. This is the three-step "Safety" dance of organic synthesis!

Answer 1

The Correct Option is D

Step 1: Concept This question evaluates various fundamental functional group transformations involving carbonyl compounds and nitrogen/oxygen nucleophiles.

Step 2: Meaning We must verify the validity of each chemical process described in the statements.

Step 3: Analysis (A) Correct: Grignard addition to nitriles followed by acid hydrolysis yields ketones. (B) Correct: Acid-catalyzed addition of one equivalent of alcohol to an aldehyde forms a hemiacetal. (C) Correct: Acetals are often used as protecting groups for carbonyls to allow selective reactions elsewhere in the molecule (chemoselectivity). (D) Correct: While primary amines form imines, secondary amines react with carbonyls (having $\alpha$-hydrogens) to form enamines.

Step 4: Conclusion All four statements (A, B, C, and D) are scientifically accurate. Final Answer: (D)