Indium-catalyzed intramolecular hydroarylation of aryl propargyl ethers

Org Biomol Chem. 2015 Jan 14;13(2):379-87. doi: 10.1039/c4ob02033b. Epub 2014 Nov 7.

Abstract

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.