Reactivity of Propargylic Esters and 2-Vinylindoles under Gold Catalysis

Gold-catalyzed transformations involving propargylic esters have emerged as versatile tool, allowing access to a variety of functional structures. Furthermore, due to their easy and modular preparation they can be readily incorporated in the core of various structures offering highly functionalized products and increasingly diverse reaction manifolds. Considering these literature evidences as well as our report on the reactivity of 2-vinylindoles and N-allenamides under gold(I) catalysis, we decided to test the possibility of generating allenes in situ from propargylic esters and react them with 2- vinylindoles. Thus, through a first 1,3-acyloxy migration, followed by [4+2] cycloaddition reaction it was possible to synthetize a highly functionalized tetrahydrocarbazoles derivatives with complete regio- and diasteroselectivity.