ORGANIC
LETTERS
1999
Vol. 1, No. 12
1909-1912
Ene Reaction of Arylallyl Alkenes with
C . A Mechanistic Approach
60
Nikos Chronakis and Michael Orfanopoulos*
Department of Chemistry, UniVersity of Crete, Iraklion 71409, Crete, Greece
Received August 2, 1999
ABSTRACT
The ene reaction of arylallyl alkenes with C occurs either by a concerted mechanism or by the reversible formation of a charged or a dipolar
60
intermediate, followed by the C−H(D) breakage in a rate-limiting step.
The isolation of C60 in large quantities1 triggered a large
number of investigations, over the past 10 years, on its
chemical reactivity and physical properties. Several research
groups have reported the preparation and isolation of well
characterized [4 + 2],2 [3 + 2],3,4 and [2 + 2]5-8 mono-
adducts of C60. However, the ene functionalization of C60
has received less attention and, to our knowledge, only three
reports describe the isolation and characterization of ene
monoadducts. For example, Wu and Komatsu reported9
independently the first examples of ene addition of 1-heptene,
4-propenylanisole, and 3,5-di-tert-butyl-4-(trimethylsiloxy)-
allylbenzene to C60. Later, Miles and co-workers10 reported
an additional example of the ene reaction of C60 with
3-methylene-2,3-dihydrofuran.
Our previous mechanistic studies of the ene reaction of
several enophiles with alkenes,11 as well as the recent reports
of [2 + 2] cycloadditions8 of aryl alkenes and dienes to C60,
prompted us to investigate for the first time the mechanism
(1) (a) Kratschmer, W.; Fostiropoulos, K.; Huffman, D. R. Chem. Phys.
Lett. 1990, 170, 167. (b) Scrivens, W. A.; Bedworth, P. V.; Tour, J. M. J.
Am. Chem. Soc. 1992, 114, 7917.
(2) (a) Hirsch, A. Synthesis 1995, 895. (b) Kra¨utler, B.; Puchberger, M.
HelV. Chim. Acta 1993, 76, 1626. (b) Rubin, Y.; Khan, S.; Freedberg, D.
I.; Yeretzian, C. J. Am. Chem. Soc. 1993, 115, 344. (c) Linssen, T. G.;
Du¨rr, K.; Hirsch, A.; Hanack, M. J. Chem. Soc., Chem. Commun. 1995,
103. (d) Khan, S. I.; Oliver, A. M.; Paddon-Row: M. N.; Rubin, Y. J. Am.
Chem. Soc. 1993, 115, 4919. (e) Gu¨gel, A.; Kraus, A.; Spikermann, J.;
Belik, P.; Mu¨llen, K. Angew. Chem., Int. Ed. Engl. 1994, 33, 559. (f) Iyoda,
M.; Sultana, F.; Sasaki, S.; Yoshida, M. J. Chem. Soc., Chem. Commun.
1994, 1929. (g) Zhang, X.; Foote, C. S. J. Org. Chem. 1994, 59, 5235.
(3) (a) Suzuki, T.; Li, Q.; Khemani, K. C.; Wudl, F.; Almarsson, O¨ .
Science 1991, 254, 1186. (b) Prato, M; Suzuki, T.; Wudl, F.; Lucchini, V.;
Maggini, M. J. Am. Chem. Soc. 1993, 115, 7876. (c) Prato, M.; Bianco,
A.; Maggini, M.; Scorrano, G.; Toniolo, C.; Wudl, F. J. Org. Chem. 1993,
58, 5578. (d) Maggini, M.; Scorrano, G.; Bianco, A.; Toniolo, C.; Sijbesma,
R. P.; Wudl, F. J. Chem. Soc., Chem. Commun. 1994, 305. (e) Prato, M.;
Li, Q.; Wudl, F.; Lucchini, V. J. Am. Chem. Soc. 1993, 115, 1148. (f)
Maggini, M.; Scorrano, G.; Prato, M. J. Am. Chem. Soc. 1993, 115, 9798.
(4) (a) Isaacs, L.; Diederich, F. HelV. Chem. Acta 1993, 76, 2454. (b)
Diederich, F.; Isaacs, L.; Philp, D. J. Chem. Soc., Perkin. Trans. 1 1994,
391. (c) Isaacs, L.; Wehrsig, A.; Diederich, F. HelV. Chim. Acta 1993, 76,
1231. (d) Vasella, A.; Uhlmann, P.; Waldraff, C. A.; Diederich, F.; Thilgen,
C. Angew. Chem., Int. Ed. Engl. 1992, 31, 1388. (e) Anderson, H. L.; Faust,
R.; Rubin, Y.; Diederich, F. Angew. Chem., Int. Ed. Engl. 1994, 33, 1366.
(f) An, Y. Z.; Rubin, Y.; Schaller, C.; McEivany, S. W. J. Org. Chem.
1994, 59, 2927.
(6) (a) Zhang, X.; Romero, A.; Foote, C. S. J. Am. Chem. Soc. 1993,
115, 11024. (b) Zhang, X.; Romero, A.; Foote, C. S. J. Am. Chem. Soc.
1995, 117, 4271. (c) Zhang, X.; Fan, A.; Foote, C. S. J. Org. Chem. 1996,
61, 5456.
(7) (a) Wilson, S. R.; Kaprinidis, N.; Wu, Y.; Schuster, D. I. J. Am.
Chem. Soc. 1993, 115, 8495. (b) Wilson, S. R.; Wu, Y.; Kaprinidis, N.;
Schuster, D. I. J. Org. Chem. 1993, 58, 6548.
(8) (a) Vassilikogiannakis, G.; Orfanopoulos, M. J. Am. Chem. Soc. 1997,
119, 7394. (b) Vassilikogiannakis, G.; Orfanopoulos, M. Tetrahedron Lett.
1997, 38, 4323. (c) Vassilikogiannakis, G.; Chronakis, N.; Orfanopoulos,
M. J. Am. Chem. Soc. 1998, 120, 9911.
(9) (a) Wu, S.; Shu, L.; Fan, K. Tetrahedron Lett. 1994, 35, 919. (b)
Komatsu, K.; Murata, Y.; Sugita, N.; S. M. Wan, T. Chem. Lett. 1994,
635.
(10) Miles, W. H.; Smiley, P. M. J. Org. Chem. 1996, 61, 2559.
(11) Stephenson, L. M.; Grdina, M. J.; Orfanopoulos, M. Acc. Chem.
Res. 1980, 13, 419. (b) Orfanopoulos, M.; Smonou, I.; Foote. C. S. J. Am.
Chem. Soc. 1990, 112, 3607. (c). Orfanopoulos, M.;. Elemes, Y.; Stratakis,
M.; Jensen F. J. Am. Chem. Soc. 1991, 113, 3801. (d) Stratakis, M.;
Orfanopoulos, M.; Foote, C. S. J. Org. Chem. 1998, 63, 1315. (e) Stratakis,
M.; Vassilikogiannakis, G.; Orfanopoulos, M. Tetrahedron Lett. 1998, 39,
2393.
(5) Hoke, S. H., II; Molstad, J.; Dilattato, D.; Jay, M. J.; Carlson, D.;
Kahr, B.; Cooks, R. G. J. Org. Chem. 1992, 57, 5069.
10.1021/ol990204o CCC: $18.00 © 1999 American Chemical Society
Published on Web 11/13/1999