Grignard allylic substitution catalyzed by imidazol-2-ylidene- and imidazol-4-ylidene-magnesium complexes

Imidazol-2- and -4-yildenes, generated in situ from the corresponding imidazolium salts, catalytically activates alkyl Grignard reagents to enable SN2′-selective allylic substitution reactions under transition metal-free conditions.