Asymmetric Intramolecular Hydroamination to Construct Diverse N–N/C–N Indole Atropisomers via Cooperative Pd(0) and Chiral Phosphoric Acid Catalysis

Here we present an enantioselective intramolecular hydroamination reaction of o-aminophenyl-1,3-enynes via cooperative catalysis of Pd(0) and chiral phosphoric acid. This approach enables the efficient construction of N-N/C-N axially stereogenic indoles with broad skeletal diversity and high levels of enantioselectivity in a completely atom-economic manner. Mechanistic studies indicate that a protonation of the alkyne moiety via Pd(0) π-Lewis base activation is favored, and the chiral phosphate counteranion plays a crucial role in controlling the atroposelectivity in the ring-closure step.