Direct arylation of gem-difluorostyrenes using in situ mechanochemically generated calcium-based heavy Grignard reagents†

Abstract

In this study, we disclosed that calcium-based heavy Grignard reagents, prepared in situ through a mechanochemical method, reacted with gem-difluorostyrenes in the absence of transition-metal catalysts to afford thermodynamically less favorable (E)-monofluorostilbenes with good to high stereoselectivity. To the best of our knowledge, this is the first example of nucleophilic substitution of a C(sp²)–F bond by an arylcalcium compound.