Efficient Microwave‐Assisted Synthesis of PCBM Methanofullerenes (C60 and C70)

Abstract PCBM is a fullerene derivative (phenyl‐C 61 ‐butyric acid methyl ester) considered to be one of the best n‐type organic semiconductors and plays a relevant role in organic photovoltaic solar cells. Much effort has been devoted to the optimization of the synthesis of PCBM derivatives. In this paper, PC 61 BM and PC 71 BM fullerene mono‐adducts but also PCBM‐like derivatives are successfully prepared by a one‐step cyclopropanation reaction under microwave irradiation. The products are collected in good yields in short time, during which isomerization of the open [5,6] to the closed [6,6] form takes place in situ. In addition, with the use of two cycles of irradiation, a series of mixtures of bis‐adduct PCBM‐like derivatives were also obtained in good yields.