Palladium-Catalyzed Synthesis of Functionalized Indoles by Acylation/Allylation of 2-Alkynylanilines with Three-Membered Rings

Palladium-catalyzed synthesis of 3-acyl and -allyl indoles has been realized by merging nucleophilic cyclization of ortho-alkynylanilines with ring opening of three-membered rings such as cyclopropenones and gem-difluorinated cyclopropanes. These functionalized indoles were obtained in moderate to high yields with high stereoselectivity in both cases. This protocol provides an alternative method toward functionalized indoles under mild and redox-neutral conditions.