Search

A new and convenient one-step synthetic approach to cyclohexadiene derivatives of C60 by means of a nickel-mediated cycloaddition of bisalkynes to C60 is presented. This method for constructing a fused cyclohexadiene ring on C60 based on a nickel-promoted (2+2+2) cycloaddition of 1,6-diynes is general for various bisalkynes. Results indicate that the cycloaddition of diynes to C60 takes place across a 6,6-ring junction on the fullerene. They also demonstrate that nickel phosphine complexes can effectively promote cycloaddition of 1,6-diynes to C60.

Regioselective synthesis of bismethanofullerenes has been achieved by the reaction of C60 with methyl or ethyl propiolate in the presence of triphenylphosphine. HMBC and other spectroscopic techniques confirm that the cyclopropane rings in the bismethanofullerenes are formed across two 6.6-ring junctions of the same six-membered ring on the C60 moiety. An unusual [2+2] cycloaddition product of C60 and methylpropiolate has also been isolated. Mechanisms have been proposed for the formation of bismethanofullerens and ethenofullerene.