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 a Cu/Fe co-catalyst system that operates at 50 °C in air with water as the only reaction medium. The easy product isolation together with the recyclable catalyst aqueous system (reused at least five times, maintaining over 50% of its catalytic activity) can provide an effective environmentally benign approach to fused N-heterocycles of remarkable interest in pharmaceutical and medicinal chemistry. The ability of the hydrazone residue to act as a chelating/directing group as well as an aminating agent guarantees the success of this C–H functionalization.
Practical and sustainable preparation of pyrrolo[2,3-b]indoles by Cu/Fe catalyzed intramolecular C(sp2)–H amination
Corrieri, Matteo;Crescentini, Lucia De;Mantellini, Fabio;Mari, Giacomo;Santeusanio, Stefania;Favi, Gianfranco
2022
Abstract
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 a Cu/Fe co-catalyst system that operates at 50 °C in air with water as the only reaction medium. The easy product isolation together with the recyclable catalyst aqueous system (reused at least five times, maintaining over 50% of its catalytic activity) can provide an effective environmentally benign approach to fused N-heterocycles of remarkable interest in pharmaceutical and medicinal chemistry. The ability of the hydrazone residue to act as a chelating/directing group as well as an aminating agent guarantees the success of this C–H functionalization.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.