1386
LETTERS
SYNLETT
(1) (a) Khand, I. U.; Knox, G. R.; Pauson, P. L.; Watts, W. E. J. Chem.
Soc., Chem. Commun. 1971, 36. (b) Khand, I. U.; Knox, G. R.;
Pauson, P. L.; Watts, W. E.; Foreman, M. I. J. Chem. Soc., Perkin
Trans. 1, 1973, 977.
(6) For instance, see; Lukehart, C. M. Fundamental Transition Metal
Organometallic Chemistry; Brooks/Cole: Monterey, 1985.
(7) There is an example in which THF, a ”hard” Lewis base, is used as
a promoter for ligand substitution reactions in the synthesis of
[Cr(CO) (arene)] complexes. See: Mahaffy, C. A. L.; Pauson, P.
L.; Inorg. Synth. 1979, 19, 155.
(2) For recent reviews, see; (a) Pauson, P. L. In Organometallics in
Organic Synthesis; de Meijere, A.; tom Dieck, H. Eds.; Springer-
Verlag: Berlin, 1987, p. 233. (b) Shore, N. E. Chem. Rev. 1988, 88,
1081. (c) Shore, N. E. In Organic Reaction, Vol. 40; Paquette, L.
A. Ed.; John Wiley & Sons, Inc.: New York, 1991, p. 1. (d) Shore,
N. E. In Comprehensive Organic Synthesis, Vol. 5; Trost, B. M.;
Fleming, I. Eds.; Pergamon: Oxford, 1991, p. 1037. (e) Shore, N.
E. In Comprehensive Organometallic Chemistry II, Vol. 12; Abel,
E. W.; Stone, F. G. A.; Wilkinson, G. Eds.; Elsevier: New York,
1995, p. 703. (f) Geis, O.; Schmalz, H.-G. Angew. Chem. 1998,
110, 955; Angew. Chem., Int. Ed. Engl. 1998, 37, 911.
3
(8) Sugihara, T.; Yamada, M.; Ban, H.; Yamaguchi, M.; Kaneko, C.
Angew. Chem. 1997, 109, 2884; Angew. Chem., Int. Ed. Engl.
1997, 36, 2801.
(9) (a) Gilmont, P.; Balanchard, A. A. Inorg. Synth. 1946, 2, 238.
(b) Devasagayaraj, A.; Periasamy, M. Tetrahedron Lett. 1989, 30,
595.
(10) Dicobalt octacarbonyl was used as a freshly-prepared solution in
toluene after sublimation. Since purity of dicobalt octacarbonyl
largely influenced its catalytic activity, we recommend to use the
complexes right after purification.
(3) Leading references for applications to the synthesis of natural
products, see; (a) Billington, D. C.; Pauson, P. L.
Organometallics, 1982, 1, 5861. (b) Exon, C.; Magnus, P. J. Am.
Chem. Soc. 1983, 105, 2477. (c) Schore, N. E.; Rowley, E. G. J.
Am. Chem. Soc. 1988, 110, 5224. (d) Takano, S.; Inomata, K.;
Ogasawara, K. J. Chem. Soc., Chem. Commun. 1992, 169.
(e) Takano, S.; Inomata, K.; Ogasawara, K. Chem. Lett. 1992, 443.
(f) Yoo, S.; Lee, S.-H.; Jeong, N.; Cho, I. Tetrahedron Lett. 1993,
34, 3435. (g) Jamison, T. F.; Shambayati, S.; Crowe, W. E.;
Schreiber, S. L. J. Am. Chem. Soc. 1994, 116, 5505.
(11) The use of the old stock solution of the catalyst in toluene
sometimes gave better results than that of the freshly prepared
solution. Standing the solution for
a while might permit
contamination of water and/or air to afford more reactive catalyst
in such cases.
(12) Since dicobalt octacarbonyl is known to react with ”hard” ligands
to produce cationic and anionic complexes via redox process, an
excess amount of additives having more nucleophilic nature might
promote the decomposition of dicobalt octacarbonyl prior to
mediate the cyclization. For instance, see; Heiber, W.; Sedlmeier,
J.; Abeck, W. Chem. Ber. 1953, 86, 700.
(4) For the known catalytic systems by using Co (CO) , see;
2
8
(a) Rautenstrauch, V.; Megard, P.; Conesa, J.; Küster, W. Angew.
Chem. 1990, 102, 1441; Angew. Chem., Int. Ed. Engl. 1990, 29,
1413. (b) Jeong, N.; Hwang, S. H.; Lee, Y.; Chung, Y. K. J. Am.
Chem. Soc. 1994, 116, 3159. (c) Pagenkopf, B. L.; Livinghouse, T.
J. Am. Chem. Soc. 1996, 118, 2285. (d) Belanger, D. B.;
O’Mahony, D. J. R.; Livinghouse, T. Tetrahedron Lett. 1998,
7637.
(13) When 1a was treated with 0.2 molar equivalent of dicobalt
octacarbonyl in 1,2-dimethoxyethane at 25 °C under 7 atm of
carbon monoxide, the alkyne-dicobalt hexacarbonyl complex of
1a was produced in 90% yield based on the cobalt complex. At
lower temperature, an excess amount of 1,2-dimethoxyethane did
not decompose dicobalt octacarbonyl but promoted ligand
exchange reaction on the cobalt.
(5) For other catalysts for the Pauson-Khand type cyclization, see:
For Ti: Hicks, F. A.; Kablaoui, N. M.; Buchwald, S. L. J. Am.
Chem. Soc. 1996, 118, 9450. Hicks, F. A.; Buchwald, S. L. J. Am.
Chem. Soc. 1996, 118, 11688. For Ru: Morimoto, T.; Chatani, N.;
Fukumoto, Y.; Murai, S. J. Org. Chem. 1997, 62, 3762. Kondo, T.;
Suzuki, N.; Okada, T.; Mitsudo, T. J. Am. Chem. Soc. 1997, 119,
6187. For Rh: Koga, Y.; Kobayashi, T.; Narasaka, K. Chem. Lett.
1998, 249. Jeong, N.; Lee, S.; Sung, B. K. Organometallics, 1998,
17, 3642.
(14) Recently, Livinghouse et al. reported the intramolecular Pauson-
Khand reaction catalyzed by Co (CO) in 1,2-dimethoxyethane at
2
8
limited range of temperature. See: ref. (4d).
(15) Although Rautenstrauch et al. reported the catalytic Pauson-
Khand reaction using alkyne-Co (CO) complexes as a catalyst, it
2
6
could not be reproduced by the authors. The contamination of
water might be one of the reasons for the unreproducibility. See:
ref. (4a).