Here I have a Chemistry Olympiad question I'm doing that outlines the synthesis of Ritalin. So far I've worked out A, Anion B -, and compound C. You can see my workings, as I've attached them here too.
Nucleophilic substitution with the nucleophile $\ce{C#N-}$ produces A:
A proton is taken away from the $\alpha-\ce C$ to deprotonate it to form Anion B -:
Anion $\ce{B-}$ acts as a nucleophile and substitutes $\ce{Cl}$ to produce C:
But how would I work out the structures of D, E and F?
I'm not familiar with all the mechanisms/reactions of nitriles and am unsure how to proceed.