The Preparation of Functionalized Heteroarylmagnesium Reagents

A variety of functionalized heterocyclic Grignard reagents can be prepared using an iodine- or bromine-magnesium exchange reaction [45,79]. The electronic na- 

Usually, the bromine-magnesium exchange on heterocyclic substrates is easier compared to the aromatic counterparts. Thus, the extensive functionalization of tribromoimidazole 157 [91] is possible. The first exchange reaction occurs at the 2-position leading to the allylated derivative 158, after a copper-catalyzed allylation, in 57% yield. Treatment of 158 with a second equivalent of iPrMgBr leads to an 

---