On the gold(I)-catalyzed enantioselective addition of indole to diphenylallene via anion-binding catalysis.

Neutral dual hydrogen bond donors (HBDs) are effective catalysts that enhance the electrophilicity of substrates or the Lewis/Brønsted acidity of reagents through an anion-binding mechanism. Despite their success in various enantioselective organocatalytic reactions, their application to transition metal catalysis remains rare. Herein, we report the activation of gold(I) precatalysts by chiral ureas, leading to enantioselective hydroarylation of allenes with indoles. Experimental and computational studies support an anion-binding mechanism for gold(I) precatalyst activation. Noncovalent interactions were identified as the source of enantiodifferentiation, providing insights into the cooperativity between achiral phosphine ligands and chiral ureas.