Copper-Catalyzed Formal [4 + 2] Annulation between Alkyne and Fullerene Bromide

A copper-catalyzed reaction of arylacetylene or enyne with C60Ar5Br effects a formal [4 + 2] annulation reaction to form a dihydronaphthalene ring fused to the fullerene core. The reaction involves a formal C−H bond activation and takes place by a copper-mediated radical mechanism. This reaction takes place in 60−75% overall yield from [60]fullerene and creates axial chirality in the product because of restricted rotation of the top aryl groups.