text: Rieke zinc has attracted the greatest attention of all the Rieke metals. Interest is motivated by the ability of Rieke Zn to convert 2,5-dibromothiophenes to the corresponding polythiophene. Rieke-Zn also reacts with bromoesters to give organozinc reagents of value for the Reformatsky reaction.
  Rieke magnesium reacts with aryl halides, some even at −78 °C, to afford the corresponding Grignard reagents, often with considerable selectivity. Rieke magnesium is famous for enabling the formation of "impossible Grignard reagents" such as those derived from aryl fluorides and from 2-chloronorbornane.