Palladium-Catalyzed Aminomethylamination and Aromatization of Aminoalkenes with Aminals via C–N Bond Activation

Thanks
to the facile imine-enamine tautomerization, the β,γ-unsaturated
hydrazones have been successfully utilized as surrogates of aminodienes
for realizing the Pd-catalyzed tandem aminomethylamination/aromatization
reaction with aminals via C–N bond activation. This direct
and operationally simple protocol provides a fundamentally novel strategy
to synthesize aromatic heterocycles from alkenes in the absence of
external oxidant and base. Mechanistic studies suggested that aminal
not only functioned as an aminomethyl source but also acted as formal
oxidant and inner base to promote the aromatization.