Urazoles as Heterocyclic Directing Groups in Ru(II)-Catalyzed Annulation of N–H/C–H Bonds with Vinylene Carbonate

The development of novel directing
groups is a valuable strategy
to secure the advancement of catalytic C–H functionalization.
To illustrate the feasibility of urazoles as heterocyclic directing
groups, we herein present the ruthenium(II)-catalyzed annulation of
N–H/C–H bonds on N-aryl urazoles with
vinylene carbonate. This transformation provides the rapid construction
of triazolocinnoline derivatives as hemiaminal and dehydrated forms.
A series of mechanistic investigations and post-transformations highlighted
the amenability of the developed method.