JEE Advanced2026ChemistryAlcohols Phenols and EthersActual
Considering LiBH ₄ reduces an ester group to the corresponding alcohol and does not reduce a carboxylic acid group, the correct statement about the major products P , Q , R and S is
Options
- AP & Q are identical, and R & S are diastereomers.
- BP & Q are diastereomers, and R & S are identical.
- CP & Q are diastereomers, and R & S are diastereomers.
- DP & Q are identical, and R & S are identical.
Correct answer
C. P & Q are diastereomers, and R & S are diastereomers.
Step-by-step solution
From the given statement, LiBH₄ selectively reduces the ester group ( -CO₂Et ) to an alcohol ( -CH₂OH ) and leaves the carboxylic acid ( -CO₂H ) unchanged. Borane ( BH₃ ), on the other hand, is a well-known reagent for the chemoselective reduction of carboxylic acids to alcohols in the presence of esters. Let us analyze the first set of reactions yielding P and Q: The starting material is a 1,2-disubstituted cyclobutane derivative. At C1, the ester group ( -CO₂Et ) is on a wedge (up) and the acid group ( -CO₂H ) is