Gold-catalyzed ligand-controlled annulation for the construction of indoles and furoindoles

Abstract

We report herein a gold-catalyzed ligand-dependent cyclization strategy that enables divergent synthesis of indole and furoindole scaffolds from ynamide precursors. This switchable transformation demonstrates remarkable selectivity through rational ligand design: employing triphenylphosphine as an ancillary ligand facilitates direct indole formation, whereas the Me₄^tBuXPhos ligand promotes a tandem annulation process to construct the privileged furoindole architecture. Besides, the protocol features mild conditions, good functional group tolerance, and moderate to excellent yields.