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: 
\[ \xrightarrow{\begin{array}{l}1.\ \mathrm{Me_2C(OMe)_2},\ \mathrm{TsOH}\ \text{(cat.)}\ 2.\ \mathrm{BH_3},\ \mathrm{THF}\ 3.\ \mathrm{H_3O^{+}}\end{array}} \]
(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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