Dynamic Dual Role as Cationic Cu⁺ and Cu Alkoxide in Cu-Catalyzed Dearomative Cascade Reactions

The reactions of N-alkoxyanilines, which have an electron-donating group at the ortho position, with alcohols in the presence of cationic NHC-Cu and alkoxide cocatalysts afforded dearomative 1,4-cyclohexadiene derivatives in good yields with high product selectivities. The Cu cocatalyst dynamically plays a dual role as a Lewis acidic catalyst to promote the [1,3]-alkoxy rearrangement and a Lewis base catalyst to facilitate the 1,4-addition of the alcohol to the ortho-quinol imine intermediate through the formation of alkoxycopper species.