corresponding pyridylmagnesium chlorides at room temperature by treatment with iPrMgCl. The resulting Grignard reagents were quenched by various electrophiles to afford functionalized pyridines. The brominemagnesium exchange of some dibromopyridines was also studied.
Bromine–magnesium exchange using iPrMgCl in THF at roomtemperature on 2-, 3- and 4-bromopyridines allowed the synthesis of various functionalized pyridines. The methodology was successfully used for the synthesis of 4-azaxanthone. Moreover, single exchange reactions observed on 2,6-, 3,5-, 2,3- and 2,5-dibromopyridines, with complete regioselectivity in the case of 2,3- and 2,5-dibromopyridines, afforded