Direct arylation of alkyl fluorides using in situ mechanochemically generated calcium-based heavy Grignard reagents

Here, we report that calcium-based heavy Grignard reagents, which are easily generated by a mechanochemical method, reacted with unactivated alkyl fluorides in the absence of transition metal catalysts to form the corresponding arylated products in moderate to good yields. This is the first example of nucleophilic substitution of an inert C(sp3)–F bond by organocalcium species. Preliminary mechanistic studies based on theoretical calculations suggest that this unprecedented C(sp3)-F bond arylation is facilitated by tetrameric aryl calcium species.