Selective Synthesis of N-Cyano Sulfilimines by Dearomatizing Stable Thionium Ions

Abstract

For the selective synthesis of N-cyano sulfilimines, we have developed a new method based on the soft-soft interaction between thionium ion electrophiles and cyanonitrene nucleophiles. The stable thionium ion was successfully obtained by oxidative dearomatization using phenyliodine (III) diacetate (PIDA) in N,N-dimethylformamide (DMF). The sulfur imination reactions were tolerant to a wide range of functional groups and exhibited high selectivities and excellent yields. The existence of thionium ion intermediates was confirmed by ultraviolet/visible (UV/vis) spectroscopy and 1H NMR experiments.