Transformable Transient Directing Group-Assisted C(sp2)–H Activation: Synthesis and Late-Stage Functionalizations of o-Alkenylanilines

The isocyanate group in aryl isocyanates serves as a transformable transient directing group in a Ru(II)-catalyzed ortho olefination leading to o-alkenylanilines. In alcoholic solvents, aryl isocyanates are transformed into carbamates, which initiate the insertion of acrylates via o-C-H activation. In particular, tAmOH serves the dual role of solvent-cum transient directing mediator. The o-alkenylanilines are converted into azacoumarins and subsequently into C-4 aryl-substituted azacoumarins using aryl iodides as coupling partners via Pd(II)-catalyzed C-H functionalizations.