The base-promoted oxidative cycloaddition reaction of [60]fullerene with ethyl acetoacetate was investigated. The reaction resulted in C60 bis-2',3'-dihydrofuran derivatives, but only with the trans-1, trans-2, trans-3, and e configurations rather than any cis or trans-4 structures, demonstrating a new regioselectivity resulting from steric influence on C60 bisaddition. In addition, distribution of the bisadducts was complicated by the unsymmetrical nature of the addends, where each individual configuration may consist of several regioisomers.