Gold-Catalyzed Carboamination of Allenes by Tertiary Amines Proceeding with Benzylic Group Migration

Tertiary amines bearing a benzyl-type group (CH₂Ar) undergo Au(I)-catalyzed intramolecular addition to allenes. A formal 1,3-transfer of the CH₂Ar group takes place during the cyclization. As demonstrated by both experimental and DFT studies, these unprecedented intramolecular carboaminations involve two consecutive [3,3] rearrangements via a dearomatized intermediate. Because of the poor stability of the enamine products, protocols were developed to convert them in situ to more stable polycyclic chiral compounds.