Question

(R)-2-Iodobutane is treated with Nal in acetone and allowed stand for a long time. The product eventually formed is

• A. $(\pm )$-1,2-diiodobutane
• B. (S)-2-iodobutane
• C. (R)-2-iodobutane
• D. $(\pm )$-2-iodobutane

Answer 1

The correct option is D $(\pm )$-2-iodobutane

$I^{-}$ is a good nucleophile as well as a good leaving group. Therefore, if (R)-2-iodobutane is treated with NaI, repeated $S_{N}2$ reactions occur. As a result, eventually a racemic mixture of $(\pm )-2-$ iodobutane is obtained.

Hence, option (c) is correct.