The au(I) catalyzed activation of allenamides and their subsequent transformation into chromanes: a method for the regiocontrolled addition to the alpha- and gamma-positions of the allene unit

Au(I) activation of allenamides in the presence of phenols leads to the formation of chromanes in moderate to good yields. This catalytic process is dependent on the counterion which facilitates the activation of the in situ formed imine. Furthermore, this iminium can be intercepted by trimethylallyl silane, via the Hosomi–Sakurai reaction, giving a formal procedure for the regioselective intermolecular addition of two carbon nucleophiles to an allenamide at the α- and γ-positions.