Reduction of MnBr 2 nLiBr (n = 1,2) with 2 C 8 K in THF affords highly active Mn-graphite, which readily inserts into allyl-, alkenyl-, (substituted) aryl- and heteroaryl halides. The functionalized organomanganese compounds thus obtained may be efficiently trapped with different electrophiles such as aldehydes, anhydrides and acid chlorides, or can be cross-coupled with alkenyl halides in the presence of catalytic amounts of Fe(acac) 3 .