Regioselective Grignard Addition to the Bridgehead Double Bond of Alkylazafulleroids through N–Mg Coordination

Grignard reagents ((RMgBr)-Mg-2; R-2 = Me, p-tolyl) regioselectively attacked the alpha-carbon of the bridgehead double bond of methyl-and benzylazafulleroids (only R-2 = Me) in contrast to the beta-carbon attack for tosylazafulleroid. A DFT calculation proved the alpha-addition through the favorable interaction of Mg and the bridged nitrogen atom. The alpha-adduct further underwent methylation on basic treatment with methyl iodide.