Mechanochemical protocol facilitates the generation of arylmanganese nucleophiles from unactivated manganese metal

Abstract

The direct synthesis of organomanganese reagents from organic halides and manganese metal remains a challenge. Current solution-based approaches require the preparation of activated manganese (Rieke manganese) or the use of multiple metal additives to promote the insertion of manganese metal into a carbon–halogen bond. Here, we show that a mechanochemical ball-milling protocol facilitates the generation of various arylmanganese nucleophiles from aryl halides and commercially available, unactivated manganese metal without the need for complicated pre-activation processes and metal additives. These manganese-based carbon nucleophiles can be used directly for one-pot addition reactions with various electrophiles and palladium-catalyzed cross-coupling reactions under bulk-solvent-free mechanochemical conditions. Importantly, all experimental operations can be conducted under atmospheric conditions.