ORGANIC
LETTERS
2
000
Vol. 2, No. 13
919-1921
Stepwise Synthesis of Fullerene
-
1
Cyclopentadienide R C and Indenide
5
60
-
R C . An Approach to Fully
3
60
Unsymmetrically Substituted Derivatives
,†
Masaya Sawamura,* Motoki Toganoh, Kazuhiro Suzuki, Atsushi Hirai,
Hitoshi Iikura, and Eiichi Nakamura*
Department of Chemistry, The UniVersity of Tokyo, Hongo, Bunkyo-ku,
Tokyo 113-0033, Japan
Received April 27, 2000
ABSTRACT
Fullerene cyclopentadienide (PhCH
2
)
2
Ph
3
C
60- and indenide (PhCH
2
)
2
PhC60-, each bearing two different organic groups, were efficiently synthesized
) or a Grignard reagent (PhMgBr) followed
through regioselective reactions of 1,4-(PhCH
2
)
2
C60 with an organocopper reagent (PhMgBr/CuBr‚SMe
2
t
by deprotonation with KO Bu.
We reported earlier the synthesis of cyclopentadienes
We are currently postulating that the 5-fold organocopper
-
(R
5
HC60; R ) Ar, Me) and cyclopentadienides (R
5
C
60
)
addition to C60 proceeds through a sequential addition/
-
embedded in C60 through quantitative 5-fold organocopper
2
oxidation process involving nucleophilic attacks of R Cu
1
addition to C60. The pentakis addition is so effective that a
species and one-electron oxidation by a Cu(I) salt. Formation
-
2
variety of R
5
C
60 compounds have been prepared, in many
of a 1,4-diorgano-1,4-dihydro[60]fullerene (1,4-R
2
C60) and
cases, in a quantitative yield; nonetheless, the method is
totally unsuitable for the synthesis of compounds bearing
different R groups or for the synthesis of C60 derivatives
bearing fewer than five substituents. Here we report strategies
for the installation of two different R groups totaling three
and five in number as demonstrated through synthesis of new
1,4,11,30-tetraorgano-1,4,11,30-tetrahydro-[60]fullerene
3
(1,4,11,30-R
tulated. Along such a line of reasoning, we considered that
the reaction of 1,4-R 60 with an organocopper reagent
4
C60) as transient intermediates are being pos-
2
C
(2) (a) Nagashima, H.; Terasaki, H.; Kimura, E.; Nakajima, K.; Itoh, K.
J. Org. Chem. 1994, 59, 1246-1248. (b) Subramanian, R.; Kadish, M. K.;
Vijayashree, N. M.; Gao, X.; Jones, T. M.; Miller, D. M.; Krause, K. L.;
Suenobu, T.; Fukuzumi, S. J. Phys. Chem. 1996, 100, 16327-16335. (c)
Miki, S.; Kitao, M.; Fukunishi, K. Tetrahedron Lett. 1996, 37, 2049-2052.
(d) Kitagawa, T.; Tanaka, T.; Tanaka, Y.; Takeuchi, K.; Komatsu, K. J.
Org. Chem. 1995, 60, 1490-1491. (e) Wang, G.-W.; Murata, Y.; Komatsu,
K.; Wan, T. S. M. J. Chem. Soc., Chem. Commun. 1996, 2059-2060. (f)
Fukuzumi, S.; Suenobu, T.; Hirasaka, T.; Arakawa, R.; Kadish, K. M. J.
Am. Chem. Soc. 1998, 120, 9220-9227.
+
-
cyclopentadienide and indenides, K [(PhCH
2
)
2
Ph
3
C60] (3)
+
-
and K [(PhCH
2
2
) PhC60] (5).
†
E-mail: sawamura@chem.s.u-tokyo.ac.jp.
1) (a) Sawamura, M.; Iikura, H.; Nakamura, E. J. Am. Chem. Soc. 1996,
(
1
18, 12850-12851. (b) Sawamura, M.; Iikura, H.; Ohama, T.; Hackler, U.
E.; Nakamura, E. J. Organomet. Chem. 2000, 599, 32-36. (c) Sawamura,
M.; Toganoh, M.; Kuninobu, Y.; Kato, S.; Nakamura, E. Chem. Lett. 2000,
2
62-263. (d) Sawamura, M.; Iikura, H.; Hirai, A.; Nakamura, E. J. Am.
(3) Murata, Y.; Shiro, M.; Komatsu, K.. J. Am. Chem. Soc. 1997, 119,
8117-8118.
Chem. Soc. 1998, 120, 8285-8286.
1
0.1021/ol005993k CCC: $19.00 © 2000 American Chemical Society
Published on Web 05/27/2000