Aza-Wolff rearrangement of N-fluoroalkyl triazoles to ketenimines†

Abstract

N-Fluoroalkylated 1,2,3-triazoles underwent a microwave-heating-assisted ring opening, nitrogen molecule elimination and concomitant group rearrangement to form isolable N-fluoroalkylketenimines. This reagent-free process is characterized by a wide scope and high efficiency and provides a new route to unexplored N-fluoroalkyl compounds. The reaction mechanism was investigated by a combination of mechanistic and computational studies. [2 + 2] cycloaddition of ketenimines with alkynes or alkenes afforded novel cyclobutenimines and cyclobutanimines, respectively. Addition of oxygen-, sulfur- and nitrogen nucleophiles to ketenimines gave new N-fluoroalkyl imidates, thioimidates and amidines.