Regioselective Synthesis of [6,6]-Phenyl-C71-Butyric Acid Methyl Esters via Sulfur Ylides for Use in Bulk Heterojunction Solar CellsSupported by: This research is partially supported by the Matching Planner Program from Japan Science and Technology Agency, Grant / Award Number: ‘MP27115662970’
Received: 26 January 2017
Accepted after revision: 07 March 2017
10 April 2017 (eFirst)
We herein report the development of a regioselective synthetic route to methanofullerenes, which have potential for application as electron acceptors in solution-processed bulk heterojunction solar cells. Sterically hindered sulfur ylide, generated in situ from their corresponding sulfonium salts in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the base, smoothly reacted with fullerene to afford the α-type [6,6]-phenyl-C71-butyric acid methyl ester (PCBM) in high purity (up to 98%). Furthermore, we successfully demonstrated the gram-scale synthesis of PCBM.