Indium-catalyzed intramolecular hydroarylation of aryl propargyl ethers.

Alonso-Marañón, L.; Martínez, M. M.; Sarandeses, L. A.; Pérez Sestelo, J.


Org. Biomol. Chem. 2015, 13, 379–387 (DOI: 10.1039/c4ob02033b).

Highlighted in: Snieckus, V.; Maheta, A. Synfacts 2015, 11, 255 (DOI: 10.1055/s-0034-1380240).

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Indium(III) halides catalyze efficiently the intramolecular hydroarylation (IMHA) of aryl propargyl ethers. The reaction proceeds regioselectively with terminal and internal alkynes bearing electron-rich and electron-deficient substituents in the benzenes and alkynes affording only the 6-endo-dig cyclization product. Additionally, a sequential indium-catalyzed IMHA and palladium-catalyzed Sonogashira coupling can be performed in one reaction vessel. Experiments with deuterium support a mechanism through electrophilic aromatic substitution.