Cu(II)-promoted transformations of α-thienylcarbinols into spirothienooxindoles: regioselective halogenation of dienyl sulfethers containing electron-rich aryl rings.

Under the promotion of Cu(II) salts, the α-thienylcarbinols with an N-phenyl carbonyl group at the other α-position are converted into three different ranges of spirothienooxindoles involving dearomatizing Friedel-Crafts reaction. In addition, the unprecedented regioselective CuX(2)-mediated C-H functionalization/halogenation of dienyl sulfether containing electron-rich aryl rings is presented.