Highly Efficient One-Pot Access to Functionalized Arylboronic Acids via Noncryogenic Bromine/Magnesium Exchanges

A general and convenient protocol for the electrophilic borylation of aryl Grignard reagents prepared from arylbromides by direct insertion of magnesium in the presence of LiCl or by Mg/Br exchange with (PrMgCl)-Pr-l center dot LiCl has been developed. Various aryl boronic acids were synthesized in a straightforward manner in excellent yields at 0 degrees C.