A Mild Two-Step Synthesis of Structurally Valuable Indole-Fused Derivatives

A mild two-step synthetic approach for the preparation of structurally valuable indolo[3′,2′:4,5]pyrrolo[3,2,1-kl]phenothiazines has been developed. In this work, cyclohexanone was used as the key bridge to connect the indole and phenothiazine frameworks to construct a structurally valuable indole-fused derivative. The present protocol achieved the cascade construction of multiple C–hetero bonds, affording a convenient approach access to hexacyclic-fused system that contained both indole and phenothiazine, two privileged skeletons.