ORGANIC
LETTERS
2003
Vol. 5, No. 3
365-368
Efficient and General Synthetic Method
for Preparing Oligoenynes with Either
trans- or cis-Olefinic Configuration
Yuuki Takayama, Christophe Delas, Kenji Muraoka, and Fumie Sato*
Department of Biomolecular Engineering, Tokyo Institute of Technology,
4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan
Received December 10, 2002
ABSTRACT
Efficient and practical synthesis of a variety of 1-iodo-4-trimethylsilylbut-1-en-3-yne derivatives with trans- and cis-olefinic configuration, and
their repeated use as building blocks for the synthesis of trans- and cis-oligoenynes, respectively, are described.
Linear polymers and oligomers containing an iteratively
π-conjugated carbon scaffold such as the ene-, enyne-,
endiyne-, and yne-scaffold exhibit a variety of interesting
electronic and optical properties.1 Because variations in their
molecular structure such as the chain length, olefin-geometry,
olefinic substituent, and end-capping group can result in
significant modifications of their properties, the development
of synthetic methodology which allows access to a wide
range of each of these π-conjugated compounds has attracted
continuing interest.2 Herein, we report a highly efficient and
general synthetic method for preparing oligoenynes with
either trans- or cis-olefinic configuration. Polymers and
oligomers having an enyne-scaffold can be prepared by
topochemical solid-state polymerization of suitably prear-
ranged and substituted buta-1,3-diynes,3 a requirement,
however, that severely limits their accessibility. Wudl and
Biter reported a synthetic method for preparing a systematic
series of trans-oligoenynes using the coupling reaction of
an alkynylmetal compound with trans-1,2-dihalo ethylene
as the key reaction.4 However, extension of this coupling
method for synthesizing oligoenynes having olefinic sub-
stituent(s) failed.5 An iterative approach to cis-oligoenynes
with the Sonogashira coupling as the key reaction was
reported by Hirsch and co-workers that allowed preparation
of some kinds of oligoenyne with up to four triple and three
double bonds, albeit the overall yield was rather low.6
(3) (a) Wegner, G. Z. Naturforsch. 1969, 24b, 824-832. (b) Wenz, G.;
Mu¨ller, M. A.; Schmidt, M.; Wegner, G. Macromolecules 1984, 17, 837-
850. (c) Sarkar, A.; Okada, S.; Matsuzawa, H.; Matsuda, H.; Nakanishi, H.
J. Mater. Chem. 2000, 10, 819-828 and references therein.
(4) Wudl, F.; Bitler, S. P. J. Am. Chem. Soc. 1986, 108, 4685-4687.
(5) (a) Giesa, R.; Schulz, R. C. Polym. Int. 1994, 33, 43-60. (b) Crousse,
B.; Alami, M.; Linstrumelle, G. Tetrahedron Lett. 1995, 36, 4245-4248.
(6) (a) Kosinski, C.; Hirsch, A.; Heinemann, F. W.; Hampel, F. Eur. J.
Org. Chem. 2001, 3879-3890. (b) See also: Bharucha, K. N.; Marsh, R.
M.; Minto, R. E.; Bergman, R. G. J. Am. Chem. Soc. 1992, 114, 3120-
3121.
(1) (a) Kraft, A.; Grimsdale, A. C.; Holmes, A. B. Angew. Chem., Int.
Ed. 1998, 37, 402-428. (b) Tykwinski, R. R.; Gubler, U.; Martin, R. E.;
Diederich, F.; Bosshard, C.; Gu¨nter, P. J. Phys. Chem. B 1998, 102, 4451-
4465.
(2) (a) Tour, J. M. Chem. ReV. 1996, 96, 537-553. (b) Martin, R. E.;
Diederich, F. Angew. Chem., Int. Ed. 1999, 38, 1350-1377. (c) Diederich,
F.; Gobbi, L. Top. Curr. Chem. 1999, 201, 43-79. (d) Diederich, F. Chem,
Commun. 2001, 219-227. (e) Nielsen, M. B.; Diederich, F. Synlett 2002,
544-552.
10.1021/ol0274413 CCC: $25.00 © 2003 American Chemical Society
Published on Web 01/11/2003