COMEDK2024Morning ShiftChemistryAldehydes and KetonesActual
Identify the Reagents I and II to be used in the course of the given reactions.
Options
- AReagent I: Zn / Hg in conc. HCl Reagent II: [ Ag ( NH ₃ )₂ ]⁺
- BReagent I: H ₂ / Pd - BaSO ₄ Reagent II: CrO ₃ / ( CH ₃ CO )₂
- CReagent I: NH ₂ NH ₂ / KOH Reagent II: Cr ₂ O ₇ ²⁻ / H ⁺
- DReagent I: DIBAL- H / H ₂ O Reagent II: conc. KOH / heat
Correct answer
D. Reagent I: DIBAL- H / H ₂ O Reagent II: conc. KOH / heat
Step-by-step solution
Starting material [A] is 1-chloro-1-formylcyclohexan-4-one. Cu²⁺/OH^- oxidises the aldehyde to carboxylic acid (ketone unaffected). [B] = 1-chlorocyclohexan-4-one-1-carboxylic acid. C₂H₅OH/H^+ esterifies the carboxylic acid. [C] = ethyl 1-chlorocyclohexan-4-one-1-carboxylate. Reagent I (DIBAL-H/ H₂O ): Reduces the ester group selectively to an aldehyde, giving 1-chloro-4-oxocyclohexane-1-carbaldehyde. This compound has an aldehyde on a quaternary carbon (no -hydrogens). Reagent II (conc. KOH/heat): An aldehyde with