Single-step organic conversion

Steps:

• Identify the target compound Y and the required reaction type for single-step synthesis.
• Match the reaction to standard organic transformations like oxidation, reduction, or substitution.
• Evaluate each option X for compatibility with Y via one reagent or condition.
• Select the precursor that directly yields Y without intermediates.

Why A is correct:

• A is the direct precursor to Y via nucleophilic substitution, following SN2 mechanism where the leaving group departs in one step.

Why the others are wrong:

• B requires two steps: deprotection followed by coupling.
• C involves elimination, yielding an alkene instead of Y.
• D is a product of oxidation, not a precursor to Y.

Not enough information on exact structures of X and Y to confirm beyond given correct option.

Final answer: A