An unprecedented synthesis of polysubstituted indole-fused pyridazines (azacarbolines) from α-indolylhydrazones under oxidative conditions using a combination of iodylbenzene (PhIO 2 ) and trifluoroacetic acid (TFA) has been developed. This transformation is conducted without the need for transition metals, harsh conditions, or an inert atmosphere.

Substituted 1‐aminopyrroles are easily accessible by iron‐catalyzed cascade reaction of 1,2‐diaza‐1,3‐dienes. Mechanistically, a formal [3+2] cyclodimerization is hypothesized to proceed through a [4+2] cyclodimerization of 4‐substitued 1,2‐diaza‐1,3‐dienes followed by intramolecular ring closure to fused diaziridin‐pyrrolines which is successively opened to undergo a ring contraction process and consequently generate the desired pyrrole moiety. The presence of activated hydrogen in the terminal position of the azo‐enic moiety is crucial for the synthesis of pyrroles.

A practical, robust and chemoselective approach toward the synthesis of pyrrolo[2,3-b]indoles via direct intramolecular C–H bond amination of α-indolylhydrazones has been achieved. This base- and oxidant-free chemoselective transformation relies on...

An oxidative cyclization of electron‐rich α‐arylhydrazones promoted by phenyliodine bis(trifluoroacetate) (PIFA) has been accomplished. This metal‐free, chemoselective transformation allows to obtain synthetically and medicinally important N‐amino‐1H‐indoles, obviating the need for pre‐functionalization of substrates.