Аннотация:
The protonation of the E/Z mixture of pyrrole-2-carboxaldehyde oxime (CF3COOH, Et2O or CDCl3, room temperature) gives Z-configured pyrrole-2-carboxaldehyde oxime cations exclusively. The NMR (1H, 13C and 15N) analysis and quantum chemical calculations [B3LYP/6-311G(d,p)] imply the stereospecific through-space stabilization of these cations by the oxime hydroxyl.