A novel dearomatization/rearomatization/cyclization oxonium ylide trapping process is well developed via a dirhodium(II) acetate and phosphoric acid cooperatively catalyzed multi-component reaction of diazo-ketones with alcohols and azonaphthalenes. This protocol provides an efficient route to synthesize N-substituted 1-amino-indole derivatives in good yield under mild reaction conditions.
![Graphical abstract: A Rh(ii)/phosphoric acid co-catalyzed three-component reaction of diazo-ketones with alcohols and azonaphthalenes: access to indole derivatives via a formal [3 + 2]-cycloaddition](http://hg.y866.cn/compound/lib/scimg/usr/1/D0OB02189J.jpg)
