N-Alkylation of Amines with Alcohols Catalyzed by a Water-Soluble Cp*Iridium Complex
351, 2903–2911; c) B. Blank, S. Michlik, R. Kempe,
Chem. Eur. J. 2009, 15, 3790–3799; d) D. Gnanamgari,
E. L. O. Sauer, N. D. Schley, C. Butler, C. D. Incarvito,
R. H. Crabtree, Organometallics 2009, 28, 321–325;
e) A. P. da Costa, M. Sanaffl, E. Peris, B. Royo, Dalton
Trans. 2009, 6960–6966; f) Y.-H. Chang, C.-F. Fu, Y.-H.
Liu, S.-M. Peng, J.-T. Chen, S.-T. Liu, Dalton Trans.
2009, 861–867; g) D. Balcells, A. Nova, E. Clot, D.
Gnanamgari, R. H. Crabtree, O. Eisenstein, Organome-
tallics 2008, 27, 2529–2535; h) A. P. da Costa, M. Vicia-
no, M. Sanaffl, S. Merino, J. Tejeda, E. Peris, B. Royo,
Organometallics 2008, 27, 1305–1309; i) B. Blank, M.
Madalska, R. Kempe, Adv. Synth. Catal. 2008, 350,
749–758; j) A. Prades, R. Corberµn, M. Poyatos, E.
Peris, Chem. Eur. J. 2008, 14, 11474–11479; k) G.
Cami-Kobeci, P. A. Slatford, M. K. Whittlesey, J. M. J.
Williams, Bioorg. Med. Chem. Lett. 2005, 15, 535–537;
l) G. Cami-Kobeci, J. M. J. Williams, Chem. Commun.
2004, 1072–1073.
3095–3165; c) U. M. Lindstrçm, Chem. Rev. 2002, 102,
2751–2772; d) S. Kobayashi, K. Manabe, Acc. Chem.
Res. 2002, 35, 209–217; e) K. Manabe, S. Kobayashi,
Chem. Eur. J. 2002, 8, 4094–4101.
[10] a) O. Saidi, A. J. Blacker, G. W. Lamb, S. P. Marsden,
J. E. Taylor, J. M. J. Williams, Org. Process Res. Dev.
2010, 14, 1046–1049; b) O. Saidi, A. J. Blacker, M. M.
Farah, S. P. Marsden, J. M. J. Williams, Chem. Commun.
2010, 1541–1543; c) T. Nishikata, B. H. Lipshutz, Org.
Lett. 2009, 11, 2377–2379; d) L. U. Nordstrøm, R.
Madsen, Chem. Commun. 2007, 5034–5036; e) S.-C.
Yang, Y.-C. Hsu, K.-H. Gan, Tetrahedron 2006, 62,
3949–3958.
[11] R. Kawahara, K. Fujita, R. Yamaguchi, J. Am. Chem.
Soc. 2010, 132, 15108–15111.
[12] Very recently, Williams et al. reported the [Cp*IrI2]2-
catalyzed N-alkylation of amines with alcohols in water
(refs.[10a,10b]). The alkylation of primary amines with pri-
mary alcohols in water has been achieved in good to
high yields, while the scope of the catalytic system
seems to be rather limited, and the alkylation of secon-
dary amines in water resulted in lower yields.
[6] a) K. Fujita, Y. Enoki, R. Yamaguchi, Tetrahedron
2008, 64, 1943–1954; b) K. Fujita, T. Fujii, R. Yamagu-
chi, Org. Lett. 2004, 6, 3525–3528; c) K. Fujita, Z. Li,
N. Ozeki, R. Yamaguchi, Tetrahedron Lett. 2003, 44,
2687–2690; d) K. Fujita, K. Yamamoto, R. Yamaguchi,
Org. Lett. 2002, 4, 2691–2694.
[13] We have previously reported the similar effect of coun-
teranions (ref.[11]). The superiority of the catalyst 3
having iodide (IÀ) as a counteranion among the cata-
lysts 1–3 could be attributed to the differences of activi-
ties for the transfer hydrogenation of the iminic inter-
mediate (see the plausible mechanism shown in
Scheme 2). There have been many examples that
iodide exhibits a positive effect in the transition metal-
catalyzed hydrogenation of imines; a) F. Spindler, B.
Pugin, H.-U. Blaser, Angew. Chem. 1990, 102, 561–562;
Angew. Chem. Int. Ed. Engl. 1990, 29, 558–559;
b) Y. N. C. Chan, J. A. Osborn, J. Am. Chem. Soc. 1990,
112, 9400–9401; c) A. Togni, Angew. Chem. 1996, 108,
1581–1583; Angew. Chem. Int. Ed. Engl. 1996, 35,
1475–1477; d) D. Xiao, X. Zhang, Angew. Chem. 2001,
113, 3533–3536; Angew. Chem. Int. Ed. 2001, 40, 3425–
3428; e) E. Guiu, B. MuÇoz, S. Castillꢁn, C. Claver,
Adv. Synth. Catal. 2003, 345, 169–171.
[7] a) M. H. S. A. Hamid, C. L. Allen, G. W. Lamb, A. C.
Maxwell, H. C. Maytum, A. J. A. Watson, J. M. J. Wil-
liams, J. Am. Chem. Soc. 2009, 131, 1766–1774; b) A.
Tillack, D. Hollmann, K. Mevius, D. Michalik, S. Bähn,
M. Beller, Eur. J. Org. Chem. 2008, 4745–4750; c) D.
Hollmann, A. Tillack, D. Michalik, R. Jackstell, M.
Beller, Chem. Asian J. 2007, 2, 403–410; d) M. H. S. A.
Hamid, J. M. J. Williams, Tetrahedron Lett. 2007, 48,
8263–8265; e) S. Naskar, M. Bhattacharjee, Tetrahe-
dron Lett. 2007, 48, 3367–3370; f) M. H. S. A. Hamid,
J. M. J. Williams, Chem. Commun. 2007, 725–727; g) A.
Tillack, D. Hollmann, D. Michalik, M. Beller, Tetrahe-
dron Lett. 2006, 47, 8881–8885; h) A. Del Zotto, W.
Baratta, M. Sandri, G. Verardo, P. Rigo, Eur. J. Inorg.
Chem. 2004, 524–529; i) R. A. T. M. Abbenhuis, J.
Boersma, G. van Koten, J. Org. Chem. 1998, 63, 4282–
4290; j) Y. Watanabe, Y. Morisaki, T. Kondo, T. Mitsu-
do, J. Org. Chem. 1996, 61, 4214–4218; k) S. Ganguly,
D. M. Roundhill, Polyhedron 1990, 9, 2517–2526; l) G.
Bitsi, E. Schleiffer, F. Antoni, G. Jenner, J. Organomet.
Chem. 1989, 373, 343–352; m) G. Jenner, J. Mol. Catal.
1989, 55, 241–246; n) J. A. Marsella, J. Org. Chem.
1987, 52, 467–468; o) Y. Watanabe, Y. Tsuji, H. Ige, Y.
Ohsugi, T. Ohta, J. Org. Chem. 1984, 49, 3359–3363;
p) S.-I. Murahashi, K. Kondo, T. Hakata, Tetrahedron
Lett. 1982, 23, 229–232; q) A. Arcelli, B.-T. Khai, G.
Porzi, J. Organomet. Chem. 1982, 235, 93–96; r) Y. Wa-
tanabe, Y. Tsuji, Y. Ohsugi, Tetrahedron Lett. 1981, 22,
2667–2670.
[14] For example, see refs.[2c,6b,6d,10a,10d] See also; a) A. J.
Blacker, M. M. Farah, M. I. Hall, S. P. Marsden, O.
Saidi, J. M. J. Williams, Org. Lett. 2009, 11, 2039–2042;
b) R. Yamaguchi, S. Kawagoe, C. Asai, K. Fujita, Org.
Lett. 2008, 10, 181–184.
[15] We have previously reported the hydrogen transfer
(Oppenauer-type) oxidation of primary and secondary
alcohols to aldehydes or ketones catalyzed by
[Cp*IrCl2]2/base system: K. Fujita, S. Furukawa, R. Ya-
maguchi, J. Organomet. Chem. 2002, 649, 289–292.
[16] A similar amide-alkoxide exchange reaction for Cp*Ir
complexes has been reported by Bergman: D. S.
Glueck, L. J. N. Winslow, R. G. Bergman, Organometal-
lics 1991, 10, 1462–1479.
[8] a) N. Tanaka, M. Hatanaka, Y. Watanabe, Chem. Lett.
1992, 575–578; b) Y. Tsuji, R. Takeuchi, H. Ogawa, Y.
Watanabe, Chem. Lett. 1986, 293–294; c) R. Grigg,
T. R. B. Mitchell, S. Sutthivaiyakit, N. Tongpenyai, J.
Chem. Soc. Chem. Commun. 1981, 611–612.
[9] For recent reviews on organic reactions in aqueous
media, see: a) A. Chanda, V. V. Fokin, Chem. Rev.
2009, 109, 725–748; b) C.-J. Li, Chem. Rev. 2005, 105,
[17] In the present reaction, the catalytic intermediates
would be IrACTHNUGTRNEUNG(III) species. There are many examples of
Cp*Ir-catalyzed hydrogen transfer reactions in which
catalytic intermediates are trivalent iridium species:
a) T. Suzuki, T. Yamada, K. Watanabe, T. Katoh,
Bioorg. Med. Chem. Lett. 2005, 15, 2583–2585; b) F.
Hanasaka, K. Fujita, R. Yamaguchi, Organometallics
2005, 24, 3422–3433; c) S. Ogo, N. Makihara, Y. Wata-
Adv. Synth. Catal. 2011, 353, 1161 – 1168
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1167