Azaanthraquinone Assembly from <i>N</i>-Propargylamino Quinone via a Au(I)-Catalyzed 6-<i>endo</i>-<i>dig</i> Cycloisomerization

A methodology to assemble the azaanthraquinone skeleton from N-propargylamino quinone by a Au(I)-catalyzed 6-endo-dig cycloisomerization was developed. The catalytic process was applied to the synthesis of alkaloid cleistopholine and its analogues. A mechanism involving benign nucleophilicity of the aminoquinone was proposed.