The chiral secondary bromide shown (single enantiomer) reacts with NaI in dry acetone for a short time, by a clean S_N2 pathway. What is the stereochemical result at the stereocentre?

A single enantiomer with inverted spatial arrangement (Walden inversion)

A single enantiomer with retained spatial arrangement

A single enantiomer with inverted spatial arrangement (Walden inversion)

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The chiral secondary bromide shown (single enantiomer) reacts with $NaI$ in dry acetone for a short time, by a clean $S X_{N} 2$ pathway. What is the stereochemical result at the stereocentre?

AA single enantiomer with retained spatial arrangement
BA racemic mixture
CA single enantiomer with inverted spatial arrangement (Walden inversion)
DA meso compound

Answer: C

The compound is (S)-2-bromobutane.

S X_{N} 2

proceeds by backside attack, so the stereocentre undergoes Walden inversion and a single enantiomer, (R)-2-iodobutane, is formed (labels checked with RDKit: reactant S, product R).

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The chiral secondary bromide shown (single enantiomer) reacts with NaI in dry acetone for a short time, by a clean SXN​2 pathway. What is the stereochemical result at the stereocentre?

Answer: C

More questions on Stereochemical outcome of substitution on drawn chiral substrates

The chiral secondary bromide shown (single enantiomer) reacts with $NaI$ in dry acetone for a short time, by a clean $S X_{N} 2$ pathway. What is the stereochemical result at the stereocentre?