Intramolecular Carbonylative C-H Functionalization of 1,2,3- Triazoles for the Synthesis of Triazolo[1,5- a]indolones.

This study presents a synthesis of 4 H-[1,2,3]triazolo[1,5- a]indol-4-ones. The key step in the synthesis of this new heterocyclic scaffold is an intramolecular cyclization via an unprecedented carbonylative C-H functionalization of 1-(2-bromoaryl)-1,2,3-triazoles. Isotopic labelling of the carbonyl carbon atom is possible using near stoichiometric amounts of 13CO. Additionally, an alternative pathway via carbonylative Sonogashira coupling followed by a two-step, one-pot azidation/cycloaddition is also investigated, giving rise to the same scaffold. [ABSTRACT FROM AUTHOR]