Palladium-Catalyzed Cyclization: Regioselectivity and Structure of Arene-Fused C60 Derivatives.

The palladium-catalyzed cyclization on the fullerene C60 cage has been achieved using several aryl halides and C60. This reaction was found to be accelerated by the addition of pivalic acid, which can be rationally explained by the computational study based on the concerted metalation-deprotonation mechanism. We also demonstrated the regioselective π-functionalization using prefunctionalized designed molecules possessing the same substructure on the C60 cage. The single crystal X-ray analysis and electrostatic potential map revealed that the orientation of entrapped H2O inside the naphthalene-fused open-cage C60 derivative is electrostatically demanded due to the naphthalene-fusion and construction of the opening.