Palladium-catalyzed vinylation of indoles with vinyl ethers via deoxygenative coupling

Indole is a promising heteroarene in many natural products and pharmaceuticals; therefore, various synthetic methods for indole functionalizations have arisen in recent years. Herein, we report a Pd-catalyzed deoxygenative coupling for the N-vinylation of indoles by employing vinyl ethers. The vinylated indoles could be readily prepared in good to excellent yields with N1-regioselectivity regardless of the electronic characteristics and substitution patterns of indole substrates. Some indole-based pharmaceutical molecules, such as gramine, evodiamine, rutaecarpine, and melatonine, are also successfully vinylated. Moreover, carbazoles and indazoles are shown to participate. Additionally, vinylated indole can readily transform into structurally interesting indole derivatives.