Gold(I)-catalyzed dynamic kinetic enantioselective intramolecular hydroamination of allenes

Treatment of benzyl 6-methyl-2,2-diphenyl-4,5-octadienyl carbamate (2a) with a catalytic 1:2 mixture of [(S )-3,5-t -Bu-4-MeO-MeOBIPHEP]AU(2)Cl(2) [(S )-1] and AgClO4 (5 Mol %) led to isolation of a 3.1:1 mixture of (R ,Z)-3a and (R ,E)-3a in 94% combined yield with 96 and 76% ee, respectively. Analyses of concentration versus time and/or conversion plots for the reaction of both racemic and enantiomerically enriched 2a with 1 were consistent with conversion of (R )-2a to (R ,Z)-3a in the matched reaction manifold and conversion of (S )-2a to (R ,E)-3a in the mismatched reaction manifold via the net anti addition of Au and N across the internal C = C bond of 2a.