POCl₃/Sulfoxide and AcCl/Sulfoxide Mediated Chlorination of Pyrrolo[2,1-<i>a</i>]isoquinolines

Abstract

We have developed an efficient chlorination of pyrrolo[2,1-<i>a</i>]isoquinoline derivatives using POCl₃ as the chlorine source and tetramethylene sulfoxide as a promoter. A series of pyrrolo[2,1-<i>a</i>]isoquinolines, polysubstituted pyrroles, and naphthols have been readily chlorinated under mild reaction conditions (26 examples, up to >99% yield). AcCl can also act as the chlorine source competently in this chlorination reaction.