Palladium-Catalyzed Oxidative Amination of α‑Olefins with Indoles

Herein we report the use of indoles, one of the most
common nitrogen-containing
heterocycles in FDA-approved drugs, as nucleophiles in the Pd-catalyzed
aza-Wacker reaction. This N-functionalization of
indoles is a Markovnikov selective olefin functionalization of simple
alkenes using catalytic Pd­(NPhth)2(PhCN)2 and
O2 as the terminal oxidant in the presence of catalytic
Bu4NBr. Various substituted indoles and alkenes are found
to participate; 21 examples are presented with yields ranging from
41 to 97% isolated yield. Additionally, lactams and oxazolidinones
are shown to participate under the reaction conditions. Mechanistic
investigations suggest that the phthalimide ligand and Bu4NBr additive slow undesired side reactions: indole decomposition
and olefin isomerization, respectively.