Question

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

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

Answer 1

Answer: (C)

($\pm$)-2-iodobutane

Answer 2

I is a good nucleophile as well as a good leaving group. Therefore, if (R)-2-iodobutane is treated with NaI, repeated S2 reactions occur. As a result, eventually a racemic mixture of $\left(\pm\right)$-2-iodobutane is obtained.