Synthesis of fused 1-aminoindole polycycles by a sequence of palladium-catalyzed N-H and C(sp²)-H arylations

An efficient Pd-catalyzed selective intramolecular arylation of functionalized N,N'-substituted 1-aminoindoles has been reported. In all cases, the reactions take place rapidly in DMA and efficiently proceed in the presence of a Pd(OAc)₂/Dpephos catalytic system, furnishing the fused indolo[2,1-a]phthalazines in high yields. Additionally, the one-pot double C-H arylation at positions C-2 and C-3 of N,N'-substituted 1-aminoindoles is effective and leads to unknown complex scaffolds of biological interest.