Question

Identify the correct set(s) in which the reactant and reagent are correctly matched to get \(\mathrm{C_6H_5CHO}\) from the following \[ \begin{aligned} \text{I. }&\mathrm{C_6H_5CN} \;\xrightarrow[\mathrm{H_2O}]{\mathrm{DIBAL\!-\!H}} \text{II. }&\mathrm{C_6H_5COCl} \;\xrightarrow[\mathrm{Pd\!-\!BaSO_4}]{\mathrm{H_2}} \text{III. }&\mathrm{C_6H_5COOC_2H_5} \;\xrightarrow[\mathrm{H_2O}]{\mathrm{DIBAL\!-\!H}} \end{aligned} \] The correct answer is

• A. I only
• B. I, II only
• C. II, III only
• D. I, II, III

Hint:

DIBAL-H is a selective reducing agent. \[ \boxed{ \begin{aligned} \text{Nitrile} &\rightarrow \text{Aldehyde} \text{Ester} &\rightarrow \text{Aldehyde} \end{aligned} } \] Rosenmund reduction converts \[ \boxed{\text{Acid chloride} \rightarrow \text{Aldehyde}.} \]

Answer 1

The Correct Option is D

Step 1: Examine each reaction. \[ \boxed{\text{I}} \] DIBAL-H partially reduces nitriles to aldehydes after hydrolysis. \[ \mathrm{C_6H_5CN} \longrightarrow \mathrm{C_6H_5CHO} \] Hence, Statement I is correct. \[ \boxed{\text{II}} \] Rosenmund reduction converts acid chlorides into aldehydes. \[ \mathrm{C_6H_5COCl} \xrightarrow{\mathrm{H_2/Pd\!-\!BaSO_4}} \mathrm{C_6H_5CHO} \] Hence, Statement II is correct. \[ \boxed{\text{III}} \] DIBAL-H selectively reduces esters to aldehydes under controlled conditions. \[ \mathrm{C_6H_5COOC_2H_5} \longrightarrow \mathrm{C_6H_5CHO} \] Hence, Statement III is also correct. Therefore, \[ \boxed{\text{I, II and III}} \] Hence, \[ \boxed{(D)} \] is the correct answer.