Synthesis of Novel Heterocycles by Amide Activation and Umpolung Cyclization

Herein, we report
a metal-free synthesis of cyclic amidines, oxazines,
and an oxazinone under mild conditions by electrophilic amide activation.
This strategy features an unusual Umpolung cyclization mode and enables
the smooth union of α-aryl amides and diverse alkylazides, effectively
rerouting our previously reported α-amination transform.