Anodic modification of proline derivatives using a lithium perchlorate/nitromethane electrolyte solution.

[reaction: see text] N-Acyliminium cation of prolines was efficiently generated to accumulate in an undivided cell at 0 degrees C by an anodic oxidation of N-acylprolines or alpha'-phenylsulfanylated N-acylproline derivatives in a lithium perchlorate/nitromethane solution. The iminium cation intermediates gave modified prolines by a reaction with nucleophiles under mild conditions.