Convenient Syntheses of 2‐Nitrophenylsulfen‐(NPS‐)imines by Oxidation of NPS‐Protected Amines and Amino Acid Derivatives

Abstract

Abstract 2‐Nitrophenylsulfenimines 2 of large structural variety are easily available from 2‐nitrophenylsulfenamides 1 , by direct and indirect electrochemical oxidation or by using stoichiometric amounts of a triarylamine radical cation salt. In most cases the direct electrochemical method is to be preferred, because of the convenient reaction procedure and the simple workup of the products. Inter‐ and intramolecular addition of nucleophiles to the C  N double bond is possible as shown by two examples.