Mercuric Triflate-(TMU) 3 -Catalyzed Cyclization of ω-Arylalkyne Leading to Dihydronaphthalenes Mugio Nishizawa,* Hiroko Takao, Veejendra K. Yadav, † Hiroshi Imagawa, and Takumichi Sugihara Faculty of Pharmaceutical Sciences, Tokushima Bunri UniVersity, Yamashiro-cho, Tokushima 770-8514, Japan mugi@ph.bunri-u.ac.jp Received August 27, 2003 ABSTRACT Efficient arylyne cyclization catalyzed by the Hg(OTf) 2 -(TMU) 3 complex has been developed. The reaction was carried out at ambient temperature in acetonitrile, and the catalytic cycle reaches up to 1000 turnovers. Carbocyclization is an important subject of modern organic synthesis. 1 Arylalkyne cyclization catalyzed by transition metal compounds such as Ru complex, 2 GaCl 3 , 3 and PtCl 4 4 affording dihydronaphthalene derivatives, Pd(0)- or PtCl 2 - catalyzed reaction generating phenanthrenes, 5 HfCl 4 -cata- lyzed cyclization of silylarylalkyne, 6 and Pd-catalyzed cou- marin synthesis 7 have been intensively studied. Silver and mercuric salts have been employed in stoichiometric amounts to mediate the cyclization of aryl propynyl ethers. 8-10 We have developed mercury(II) trifluoromethanesulfonate, so- called mercuric triflate [hereafter Hg(OTf) 2 ], as a highly efficient olefin cyclization agent 11 and applied it for the synthesis of polycyclic terpenoids. 12 Recently, we found that the Hg(OTf) 2 and Hg(OTf) 2 -tetramethylurea (hereafter TMU) complex showed effective catalytic activity for the ² On leave from Indian Institute of Technology, Kanpur, India, as a JSPS Visiting Scientist. (1) For reviews on metal-catalyzed carbocyclization, see: (a) Ojima, I.; Tzamarioudaki, M. L. Z.; Donovan, R. J. Chem. ReV. 1996, 96, 635-662. (b) Negishi, E.; Coperet, C.; Ma, S.; Liou, S.-Y.; Liu, F. Chem. ReV. 1996, 96, 365-393. (c) Trost, B. M. Chem. Eur. J. 1998, 4, 2405-2412. (2) Chatani, N.; Inoue, H.; Ikeda, T.; Murai, S. J. Org. Chem. 2000, 65, 4913-4918. (3) Inoue, H.; Chatani, N.; Murai, S. J. Org. Chem. 2002, 67, 1414- 1417. (4) Pastine, S. J.; Youn, S. W.; Sames, D. Org. Lett. 2003, 5, 1055- 1058. (5) (a) Larock, R. C.; Doty, M. J.; Tian, Q.; Zenner, J. M. J. Org. Chem. 1997, 62, 7536-7537. (b) Fu ¨rstner, A.; Mamane, V. J. Org. Chem. 2002, 67, 6264-6267. (6) Asao, N.; Shimada, T.; Shimada. T.; Yamamoto, Y. J. Am. Chem. Soc. 2001, 123, 10899-10902. (7) (a) Trost, B. M.; Toste, F. D. J. Am. Chem. Soc. 1996, 118, 6305- 6306. (b) Jia, C.; Piao, D.; Kitamura, T.; Fujiwara, Y. J. Org. Chem. 2000, 65, 7516-7522. (8) Koch-Pomeranz, U.; Hansen, H.-J.; Schmid, H. HelV. Chim. Acta 1973, 56, 2981-3004. Although the title of this paper included a phrase “katalysielte Umlagerung von Propargyl-phenyla ¨ther”, the catalytic cycle is less than one, and it is not a catalytic process. (9) (a) Thyagarajan, B. S.; Majumdar, K. C.; Bates, D. K. Heterocycl. Chem. 1975, 12, 59-66. Although the title of this paper includes the phrase “mercuric ion-catalyzed hydration of 1-aryloxy-4-arylthio-2-butynes”, the catalytic cycle is less than 1.5, and it is not a practical catalytic process. (b) Bates, D. K.; Jones, M. C. J. Org. Chem. 1978, 43, 3856-3861. (10) Larock, R. C.; Harrison, L. W. J. Am. Chem. Soc. 1984, 106, 4218- 4227. (11) (a) Nishizawa, M.; Takenaka, H.; Nishide, H.; Hayashi, Y. Tetrahedron Lett. 1983, 24, 2581-2584. (b) Nishizawa, M.; Morikuni, E.; Asoh, K.; Kan, Y.; Uenoyama, K.; Imagawa, H. Synlett 1995, 169-170. (12) (a) Nishizawa, M.; Takenaka, H.; Hayashi, Y. J. Am. Chem. Soc. 1984, 106, 4290-4291. (b) Nishizawa, M.; Takenaka, H.; Hayashi, Y. J. Org. Chem. 1986, 51, 806. (c) Nishizawa, M.; Yamada, H.; Hayashi, Y. Tetrahedron Lett. 1986, 27, 187-190. (d) Nishizawa, M.; Yamada, H.; Hayashi, Y. J. Org. Chem. 1987, 52, 4878. (e) Nishizawa, M.; Takao, H.; Kanoh, N.; Asoh, K.; Hatakeyama, S.; Yamada, H. Tetrahedron Lett. 1994, 35, 5693-5696. (f) Nishizawa, M.; Morikuni, E.; Takeji, M.; Asoh, K.; Hyodo, I.; Imagawa, H.; Yamada, H. Synlett 1996, 927-928. (g) Nishizawa, M.; Takao, H.; Iwamoto, Y.; Yamada, H.; Imagawa, H. Synlett 1998, 76- 78. (h) Nishizawa, M.; Imagawa, H.; Hyodo, I.; Takeji, M.; Morikuni, E.; Asoh, K.; Yamada, H. Tetrahedron Lett. 1998, 39, 389-392. (i) Nishizawa, M.; Takao, H.; Iwamoto, Y.; Yamada, H.; Imagawa, H. Synlett 1998, 76- 78. (j) Imagawa, H.; Shigaraki, T.; Suzuki, T.; Takao, H.; Yamada, H.; Sugihara, T.; Nishizawa, M. Chem. Pharm. Bull. 1998, 46, 1341-1342. (k) Nishizawa, M.; Shigaraki, T.; Takao, H.; Imagawa, H.; Sugihara, T Tetrahedron Lett. 1999, 40, 1153-1156. ORGANIC LETTERS 2003 Vol. 5, No. 24 4563-4565 10.1021/ol035622e CCC: $25.00 © 2003 American Chemical Society Published on Web 10/28/2003