3584
J . Org. Chem. 1996, 61, 3584-3585
Ta ble 1. P a lla d iu m (II)-Ca ta lyzed Cycliza tion of Olefin ic
Tosyla m id es
P a lla d iu m (II)-Ca ta lyzed Cycliza tion of
Olefin ic Tosyla m id es
Richard C. Larock,* Timothy R. Hightower,
Lisa A. Hasvold, and Karl P. Peterson
Department of Chemistry, Iowa State University,
Ames, Iowa 50011
Received November 28, 1995
The palladium-catalyzed cyclization of simple olefinic
amines,1 tosylamides,2 and carboxamides3 has proven to
be a particularly valuable route to a wide variety of
nitrogen heterocycles. For example, the cyclization of
o-vinylic1d,h,2b,f and o-allylic1c-e,h anilines or their tosyl
derivatives by either stoichiometric amounts of palla-
dium(II) salts or catalytic amounts of palladium(II) salts
in the presence of benzoquinone as a reoxidant efficiently
provides indoles. We recently reported the palladium-
catalyzed conversion of alkenoic acids to unsaturated
lactones4 and enol silanes to enals and enones5 using a
remarkably simple, environmentally attractive catalyst
system consisting of 5 mol % Pd(OAc)2 under an atmo-
sphere of O2 in DMSO solvent with no additional reoxi-
dants.6,7 The recent report of one example of the cycliza-
tion of an olefinic tosylamide to an N-allylic tosylamide8
(1) For the cyclization of olefinic amines, see: (a) Pugin, B.; Venanzi,
L. M. J . Organomet. Chem. 1981, 214, 125. (b) Pugin, B.; Venanzi, L.
M. J . Am. Chem. Soc. 1983, 105, 6877. (c) Hegedus, L. S.; Allen, G. F.;
Bozell, J . J .; Waterman, E. L. J . Am. Chem. Soc. 1976, 98, 2674. (d)
Hegedus, L. S.; Allen, G. F.; Bozell, J . J .; Waterman, E. L. J . Am. Chem.
Soc. 1978, 100, 5800. (e) Hegedus, L. S. J . Mol. Catal. 1983, 19, 201.
(f) Weider, P. R.; Hegedus, L. S.; Asada, H.; D’Andreq, S. V. J . Org.
Chem. 1985, 50, 4276. (g) Hegedus, L. S.; Weider, P. R.; Mulhern, T.
A.; Asada, H.; D’Andrea, S. Gazz. Chim. Ital. 1986, 116, 213. (h)
Hegedus, L. S.; Winton, P. M.; Varaprath, S. J . Org. Chem. 1981, 46,
2215. (i) Hatano, S.; Saruwatari, M.; Isomura, K.; Taniguchi, H.
Heterocycles 1981, 15, 747. (j) Heathcock, C. H.; Stafford, J . A.; Clark,
D. L. J . Org. Chem. 1992, 57, 2575. (k) van der Schaaf, P. A.; Sutter,
J .-P.; Grellier, M.; van Mier, G. P. M.; Spek, A. L.; van Koten, G.;
Pfeffer, M. J . Am. Chem. Soc. 1994, 116, 5134. (l) Hegedus, L. S.; Allen,
G. F.; Olsen, D. J . J . Am. Chem. Soc. 1980, 102, 3583.
(2) For the cyclization of olefinic tosylamides, see ref 1e and: (a)
Hegedus, L. S.; McKearin, J . M. J . Am. Chem. Soc. 1982, 104, 2444.
(b) Kasahara, A.; Izumi, T.; Yanai, H.; Murakami, S.; Yusa, A.; Kon,
H.; Kikuchi, T.; Tsuda, S.; Kudo, N.; Takatori, M.; Nikaido, T. Bull.
Yamagata Univ. 1986, 19, 39. (c) Tamaru, Y.; Hojo, M.; Kawamura,
S.; Yoshida, Z. J . Org. Chem. 1986, 51, 4089. (d) Tamaru, Y.;
Kobayashi, T.; Kawamura, S.; Ochiai, H.; Yoshida, Z. Tetrahedron Lett.
1985, 26, 4479. (e) Tamaru, Y.; Hojo, M.; Yoshida, Z. J . Org. Chem.
1988, 53, 5731. (f) Harrington, P. J .; Hegedus, L. S.; McDaniel, K. F.
J . Am. Chem. Soc. 1987, 109, 4335. (g) van Benthem, R. A. T. M.;
Hiemstra, H.; Longarela, G. R.; Speckamp, W. N. Tetrahedron Lett.
1994, 35, 9281. (h) Tamaru, Y.; Tanigawa, H.; Itoh, S.; Kimura, M.;
Tanaka, S.; Fugami, K.; Sekiyama, T.; Yoshida, Z. Tetrahedron Lett.
1992, 33, 631. (i) Hegedus, L. S.; Holden, M. S.; McKearin, J . M. Org.
Syn. 1984, 62, 48.
a
See the text and the supporting information for these
procedures. All products gave appropriate 1H and 13C NMR, IR,
b
(3) For the cyclization of olefinic amides, see refs 1e,l, and 2d,e,g,h,
plus: (a) Hegedus, L. S.; Korte, D. E.; Wirth, R. K. J . Org. Chem. 1977,
42, 1329. (b) Saito, S.; Hara, T.; Takahashi, N.; Hirai, M.; Moriwake,
T. Synlett 1992, 237. (c) Danishefsky, S.; Taniyama, E. Tetrahedron
Lett. 1983, 24, 15. (d) Tamaru, Y.; Hojo, M.; Higashimura, H.; Yoshida,
Z. J . Am. Chem. Soc. 1988, 110, 3994. (e) J a¨ger, V.; Hu¨mmer, W.
Angew. Chem., Int. Ed. Engl. 1990, 29, 1171.
(4) Larock, R. C.; Hightower, T. R. J . Org. Chem. 1993, 58, 5298.
(5) Larock, R. C.; Hightower, T. R.; Kraus, G. A.; Hahn, P.; Zheng,
D. Tetrahedron Lett. 1995, 36, 2423.
(6) For other recent applications of this catalyst system, see ref 2g
and: (a) van Benthem, R. A. T. M.; Hiemstra, H.; Michels, J . J .;
Speckamp, W. N. J . Chem. Soc., Chem. Commun. 1994, 357. (b) van
Benthem, R. A. T. M.; Hiemstra, H.; Speckamp, W. N. J . Org. Chem.
1992, 57, 6083.
(7) For other references to the direct oxidation of Pd(0) to Pd(II)
without any additional reoxidants, see: (a) Hosokawa, T.; Takano, M.;
Kuroki, Y.; Murahashi, S. Tetrahedron Lett. 1992, 33, 6643. (b)
Hosakawa, T.; Miyagi, S.; Murahashi, S.; Sonoda, A. J . Org. Chem.
1978, 43, 2752.
and mass spectral data.
using this same catalyst system, plus earlier reports of
the cyclization of unsaturated tosylamides to N-vinylic
tosylamides1e,2a,i by other palladium(II) catalyst systems,
encourages us to report at this time our unusual results
using the Pd(OAc)2/O2 catalyst on a variety of simple
olefinic tosylamides.
We initially examined several simple olefinic tosyl-
amides using our previously developed catalyst system
(procedure A: 0.25 mmol of the tosylamide, 5 mol % Pd-
(OAc)2, 2 equiv of NaOAc, and 5 mL of DMSO under 1
atm of O2). The results of those cyclizations are reported
in Table 1, entries 1-3. In general, acyclic and cyclic
olefinic tosylamides can be cyclized to 5- and 6-membered
ring products containing an allylic nitrogen moiety. This
is in agreement with the very recent work of Andersson
(8) Ro¨nn, M.; Ba¨ckvall, J .-E.; Andersson, P. G. Tetrahedron Lett.
1995, 36, 7749.
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