Highly Regioselective Indoline Synthesis under Nickel/Photoredox Dual Catalysis

Nickel/photoredox catalysis is used
to synthesize indolines in
one step from iodoacetanilides and alkenes. Very high regioselectivity
for 3-substituted indoline products is obtained for both aliphatic
and styrenyl olefins. Mechanistic investigations indicate that oxidation
to Ni­(III) is necessary to perform the difficult C–N bond-forming
reductive elimination, producing a Ni­(I) complex, which in turn is
reduced to Ni(0). This process serves to further demonstrate the utility
of photoredox catalysts as controlled single electron transfer agents
in multioxidation state nickel catalysis.