(Solved): 7.53 In Chapter 9, we will see that an acetylide ion (formed by treatment of acetylene with a stron ...

7.53 In Chapter 9, we will see that an acetylide ion (formed by treatment of acetylene with a strong base) can serve as a nucleophile in an \( \mathrm{S}_{\mathrm{N}} 2 \) reaction: \[ \mathrm{H}-\mathrm{C} \equiv \mathrm{C}-\mathrm{H} \stackrel{\begin{array}{l} \text { Strong } \\ \text { base } \end{array}}{\longrightarrow} \mathrm{H}-\mathrm{C} \equiv \mathrm{C}: \stackrel{\mathrm{RX}}{\longrightarrow} \mathrm{H}-\mathrm{C} \equiv \mathrm{C}-\mathrm{R} \] Acetylene Acetylide ion 7.54 Consider the following \( \mathrm{S}_{\mathrm{N}} 2 \) reaction: \( \underset{\mathrm{DMF}}{\mathrm{NaCN}} \) (a) Assign the configuration of the chiral center in the substrate. (b) Assign the configuration of the chiral center in the product. (c) Does this \( \mathrm{S}_{\mathrm{N}} 2 \) process proceed with inversion of configuration? Explain.