Divergent synthesis of α-functionalized amides through selective N–O/C–C or N–O/C–C/C–N cleavage of aza-cyclobutanone oxime esters.

Herein, a novel sequential ring opening reaction of aza-cyclobutanone oxime esters with isocyanides is described. The reaction proceeded smoothly under redox-neutral and mild conditions, leading to a divergent synthesis of α-cyanomethylaminoamides, α-acyloxyamides and α-acylaminoamides. In these transformations, a selective N–O/C–C or N–O/C–C/C–N cleavage was achieved only by changing the iron-catalyst system. Among them, a rare sequential N–O/C–C/C–N cleavage process with a classical Passerini or Ugi multicomponent reaction can be executed in a single step. To the best of our knowledge, this work creates a novel reaction mode of cycloketone oximes and provides new opportunities for reaction design. [ABSTRACT FROM AUTHOR]