Meta- and Para-Difunctionalization of Arenes via a Sulfoxide-Magnesium Exchange Reaction.

The aryl sulfoxide moiety (ArSO) allows an expedient two-step meta-, para-difunctionalization of readily available diaryl sulfoxides. In the first step, the sulfoxide plays the role of a directing metalation group. In the second step, triggered by i-PrMgCl·LiCl, it becomes a leaving group and undergoes a regioselective sulfoxide−magnesium exchange.