Efficient copper-catalyzed domino synthesis of tetrazoloisoquinolines

Abstract

A novel and efficient copper-catalyzed method for the synthesis of tetrazolo[5,1-a]isoquinolines has been developed. The protocol uses readily available substituted 5-(2-halophenyl)-1H-tetrazoles and alkynes as the starting materials and inexpensive copper(I) iodide as the catalyst. The domino reaction underwent sequential copper-catalyzed Sonogashira cross-coupling and intramolecular addition of the NH from a tetrazole group to an internal alkyne.