HCl/DMSO/HFIP-Mediated Chlorination of Pyrrolo[2,1- a ]isoquinolines and Other Electron-Rich Heteroarenes.

An efficient oxidative chlorination of pyrrolo[2,1- a ]isoquinolines has been established using HCl (aq) as the chlorine source and DMSO as the terminal oxidant in HFIP at ambient temperature. A variety of chlorinated pyrrolo[2,1- a ]isoquinoline derivatives have been prepared readily in 23 to 99% yields. This chlorination strategy can be expanded to the functionalization of other electron-rich heteroarenes including substituted pyrroles, indoles, and naphthols.