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Boomerang‐Type Substitution Reaction: Reactivity of Fullerene Epoxides and a Halofullerenol
Author(s) -
Jia Zhenshan,
Zhang Xiang,
Zhang Gaihong,
Huang Shaohua,
Fang Hao,
Hu Xiangqing,
Li Yuliang,
Gan Liangbing,
Zhang Shiwei,
Zhu Daoben
Publication year - 2007
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.200600268
Subject(s) - chemistry , dabco , reactivity (psychology) , fullerene , chemoselectivity , medicinal chemistry , octane , substitution reaction , photochemistry , electron transfer , stereochemistry , organic chemistry , catalysis , medicine , alternative medicine , pathology
The C s ‐symmetric fullerene chlorohydrin C 60 (Cl)(OH)(OO t Bu) 4 reacts with 4‐dimethylaminopyridine (DMAP) and 1,4‐diazabicyclo[2.2.2]octane (DABCO) to yield two isomers with the formula C 60 (O)(OO t Bu) 4 in good yields. These isomers differ with respect to the location of the epoxy functionality. The one from DMAP is C s symmetric, whereas that from DABCO is C 1 symmetric with the epoxy group on the central pentagon. Two different mechanisms are proposed to explain the chemoselectivity of these reactions. The reaction with DMAP involves single‐electron transfer as the key step; DMAP acts as the electron donor. A combination of an oxygen‐atom shift and S N 2′′ processes (boomerang substitution) are responsible for the formation of isomer with DACBO. Various related reactions support the proposed mechanisms. The structures of new fullerene derivatives were determined by spectroscopy, single‐crystal X‐ray analysis, and chemical correlation experiments.