Q11 · CSIR-NET Chemistry, December 2014
Paper: CSIR-NET December 2014 · Subject: Organic Chemistry · Chapter: Reagents, Reaction Mechanisms & Named Reactions · Topic: Reagents, Reaction Mechanisms & Named Reactions – General · Marks: 2 · Difficulty: Medium
The major product formed in the following reaction sequence is: 
(a)
(b)
(c)
(d)
Answer
Answer: C ✓ checked by 4AB · confidence medium
Explanation
Acetone dimethyl acetal locks the α-hydroxy acid as a dioxolanone; BH₃ reduces the free CH₂COOH to CH₂OH, and acid removes the acetonide and lactonises: (S)-2-hydroxy-γ-butyrolactone with the α-OH configuration retained (c).
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