Aza-Wolff rearrangement of N-fluoroalkyl triazoles to ketenimines

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.

Automated summary

N-Fluoroalkylated 1,2,3-triazoles undergo a microwave-heating-assisted ring opening, nitrogen molecule elimination, and concomitant group rearrangement to form isolable N-fluoroalkylketenimines. This reagent-free process exhibits a wide scope and high efficiency, providing a new route to unexplored N-fluoroalkyl compounds. Mechanistic and computational studies were employed to investigate the reaction mechanism. [2 + 2] cycloaddition of ketenimines with alkynes or alkenes yields novel cyclobutenimines and cyclobutanimines, respectively. Addition of oxygen, sulfur, and nitrogen nucleophiles to ketenimines gives rise to new N-fluoroalkyl imidates, thioimidates, and amidines.