Question

why cannot aromatic primary amines be prepared by gabriel pthalimide reaction

Answer 1

because we use alpha halo esters used in this reaction

Answer 2

$\huge\textcolor{indigo}{\rm{Answer :-}}$

Aromatic primary amines can not be prepared by Gabriel Phthalimide synthesis, because aryl halides do not undergo nucleophillic substitution reaction with the anion formed by the phthalamide.