Divergent Synthesis of Chromenoindoles and Spiroindolines via Domino Reaction of Indolyl-Substituted Isocyanides with Quinone Esters.

A dearomative spirocyclization of tryptamine-derived isocyanides with quinone esters is developed for the divergent synthesis of structurally complex chromeno[2,3- b ]indole and polycyclic spiroindoline scaffolds. This domino reaction features the formation and conversion of the six-membered dihydropyran ring with an amendable N , O -aminal moiety.