A one-pot double C-H activation palladium catalyzed route to a unique class of highly functionalized thienoisoquinolines.

The synthesis of a unique class of highly functionalized 3,4-thienoisoquinolines via an efficient palladium-catalyzed one-pot, regioselective double C-H activation is presented. This class of biologically relevant compounds has been prepared in five steps from commercially available starting materials with overall yields ranging from 27 to 62%. A masked carboxylic acid was used to direct C-H activation to the typically less reactive C4 position. Additionally, the carboxylic acid provides a synthetically useful handle for further functionalization.