Highly chemo- and stereoselective Fe-catalyzed alkenylation of organomanganese reagents

Organomanganese chlorides react with alkenyl iodides, bromides and chlorides in the presence of 3% Fe(acac)(3). The reaction takes place under very mild conditions (THF-NMP, rt, 1h) to afford the substituted olefin in excellent yields with a high stereo- and chemoselectivity. Thus an unprotected keto alkenyl chloride selectively gives the corresponding keto olefin. From a preparative point of view, this procedure is the first real alternative to the Pd- and Ni-cross coupling reaction used until now.