Copyright 2008
Volume 27, Number 16, August 25, 2008
American Chemical Society
Communications Synthesis of Aryliron Complexes by Palladium-Catalyzed Transmetalation between [CpFe(CO)2I] and Aryl Grignard Reagents and Their Chemistry Directed toward Organic Synthesis Shigeo Yasuda, Hideki Yorimitsu,* and Koichiro Oshima* Department of Material Chemistry, Graduate School of Engineering, Kyoto UniVersity, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan ReceiVed June 17, 2008 Summary: Palladium-catalyzed transmetalation between [CpFe(CO)2I] and aryl Grignard reagents emerges as a new method for the synthesis of [CpFe(CO)2Ar]. The aryliron complexes thus formed are useful arylmetal reagents that become actiVe upon oxidation or UV irradiation. Thanks to the ubiquity of iron, organoiron compounds represent rare organic transition-metal compounds that we can use stoichiometrically in organic synthesis. However, the potential of organoiron compounds have not been fully developed.1 Among organoiron compounds, the coordinatively saturated aryldicarbonylcyclopentadienyliron complexes [CpFe(CO)2Ar] are easy to handle and hence can be useful as arylmetal reagents in organic synthesis. However, little is known about the concise * To whom correspondence should be addressed. E-mail: yori@ orgrxn.mbox.media.kyoto-u.ac.jp (H.Y.);
[email protected]. kyoto-u.ac.jp.(K.O.). (1) (a) Pearson, A. J. Iron Compounds in Organic Synthesis; Academic Press: London, 1994. (b) Pearson, A. J. Pure Appl. Chem. 1983, 55, 1767– 1779. (c) Kno¨lker, H.-J. Curr. Org. Synth. 2004, 1, 309–331. (d) Kno¨lker, H.-J. Chem. ReV. 2000, 100, 2941–2961. (e) Kno¨lker, H.-J. Chem. Soc. ReV. 1999, 28, 151–157. (f) Ru¨ck-Braun, K.; Mikula´s, M.; Amrhein, P. Synthesis 1999, 727–744. (g) Li, C.-L.; Liu, R.-S. Chem. ReV. 2000, 100, 3127–3161. (h) Abd-El-Aziz, A. S.; Bernardin, S. Coord. Chem. ReV. 2000, 203, 219–267. (i) Donaldson, W. A. Curr. Org. Chem. 2000, 4, 837–868. (j) Nakazawa, H.; Itazaki, M.; Kamata, K.; Ueda, K. Chem. Asian J. 2007, 2, 882–888. (k) Anson, C. E.; Malkov, A. V.; Roe, C.; Sandoe, E. J.; Stephenson, G. R. Eur. J. Org. Chem. 2008, 196–213, and references cited therein.
synthesis of [CpFe(CO)2Ar].2 Here we report a new efficient method for the synthesis of [CpFe(CO)2Ar] under palladium catalysis. Several transformations of [CpFe(CO)2Ar] are also disclosed, which will be useful in organic synthesis.3,4 As reported previously,2a our attempt at a substitution reaction of [CpFe(CO)2I] (1) with phenylmagnesium bromide in the absence of a catalyst resulted in failure, affording a poor yield of [CpFe(CO)2Ph] (2a), a significant amount of [CpFe(CO)2]2 (3), and recovered 1 (Table 1, entry 1). After extensive screening of the reaction conditions, we found that a combination of palladium acetate and diamine 4 efficiently catalyzes the phe(2) The reaction of [CpFe(CO)2I] with phenylmagnesium bromide was reported to result in a less than 12% yield of [CpFe(CO)2Ph]: (a) Li, H.-J.; Turnbull, M. M. J. Organomet. Chem. 1991, 419, 245–249. The reaction with highly reactive aryllithium: (b) Butler, I. R.; Lindsell, W. E.; Preston, P. N. J. Chem. Res., Synop. 1981, 185. The palladium-catalyzed reactions of aryl iodides with [CpFe(CO)2]ZnCl, the preparation of which requires NaK2.8: (c) Artamkina, G. A.; Mil’chenko, A. Y.; Bumagin, N. A.; Beletskaya, I. P.; Reutov, O. A. Organomet. Chem., USSR 1988, 1, 17–20. The reactions of diaryliodonium and triarylsulfonium salts with [CpFe(CO)2]Na: (d) Nesmeyanov, A. N.; Chapovsky, Y. A.; Polovyanyuk, I. V.; Makarova, L. G. J. Organomet. Chem. 1967, 7, 329–337. Decarbonylation of [CpFe(CO)2(ArCO)], which is available from [CpFe(CO)2]Na and ArCOCl: (e) Hunter, A. D.; Szigety, A. B. Organometallics 1989, 8, 2670– 2679, and references cited therein. (3) Butler, I. R.; Cullen, W. R.; Lindsell, W. E.; Preston, P. N.; Rettig, S. J. J. Chem. Soc., Chem. Commun. 1987, 439–441. (4) The coordination chemistry of [CpFe(CO)2Ar] has been summarized: Kerber, R. C. In ComprehensiVe Organometallic Chemistry II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Elsevier: Oxford, U.K., 1995; Vol. 7, Chapter 2.
10.1021/om800560m CCC: $40.75 2008 American Chemical Society Publication on Web 07/26/2008
4026 Organometallics, Vol. 27, No. 16, 2008
Communications
Table 1. Ligand Effect on Palladium-Catalyzed Arylation of 1
Table 2. Palladium-Catalyzed Arylation of 1 with ArMgBr
entry yield/% entry 1a 2 3 4 5 6 7 8 9d 10f
ligand
2a
3
1
none PPh3 P(c-C6H11)3 DPPEb TMEDAc 4 2,2′-bipyridyl IPr · HCle 4
5 73 32 15 45 73 87 81 28 87
51 9 38 37 31
