title: A scalable synthesis of methano[60]fullerene and congeners by the oxidative cyclopropanation reaction of silylmethylfullerene.
abstract: 1,2-Dihydromethano[60]fullerene and its congeners have attracted much interest, but they have been synthesized only in very low yields because of several insurmountable problems. A new three-stage synthesis involving addition of a silylmethylmagnesium chloride to [60]- and [70]fullerene and oxidation of the anionic intermediate with CuCl(2) afforded the methano[60]- and methano[70]fullerenes in 90% and 70% overall yield, respectively. The reaction with 1,4-diorgano[60]fullerene also proceeded smoothly to give a diastereomerically pure 56-π-electron fullerene that has a higher LUMO level than the parent fullerene and gave a higher open-circuit voltage and better power conversion efficiency when fabricated into an organic photovoltaic device.
authors.affiliation: Department of Chemistry, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Matsuo
authors.forename: Chang-Zhi
authors.initials: CZ
authors.lastname: Li
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Eiichi
authors.initials: E
authors.lastname: Nakamura