M.Malacria, B.Hasenknopf et al.
5.7 mmol, 8.5 equiv) in hot water (7 mL) was added dropwise. After com-
plete addition, the solution was allowed to stir for an additional 2 min.
The precipitate was then collected by filtration and washed successively
with H2O, EtOH, and Et2O.The crude product was dissolved in CH 3CN
(10 mL) and the remaining solid was removed by centrifugation.A solu-
tion of Acetone/EtOH (v/v; 1:1, 12 mL) were added to the filtrate and
then Et2O (50 mL).The white precipitate was collected by centrifugation.
Yield: 2.27 g (88%); 31P NMR (162 MHz, c=0.036 molLÀ1, CD3CN): d=
À12.06 ppm (s, 1P); IR: n˜ =2963 (m), 2936 (m), 2875 (m), 1485 (m), 1459
(m), 1382 (w), 1152 (w), 1091 (m), 1059 (s), 956 (s), 886 cmÀ1 (s); elemen-
tal analysis calcd (%) for C59.2H140.2N3.7K0.3HfO43PW11 including 3H2O
(3835.7): C 18.54, H 3.68, N 1.35, K 0.31, P 0.81, W 52.72, Hf 4.65; found:
C 18.33, H 3.56, N 1.30, K 0.29, P 0.85, W 51.68, Hf 4.67.
[2] For a recent reference on acid (POM)-catalyzed Mannich reactions,
see: N.Azizi, L.Torkiyan, M.R.Saidi,
2082.
Org. Lett. 2006, 8, 2079–
[3] For recent references: a) D.Kumar, E.Derat, A.M.Khenkin, R.
Neumann, S.Shaik, J. Am. Chem. Soc. 2005, 127, 17712–17718;
b) Y.Nakagawa, K.Kamata, M.Kotani, K.Yamaguchi, N.Mizuno,
Angew. Chem. 2005, 117, 5266–5271; Angew. Chem. Int. Ed. 2005,
44, 5136–5141; c) O.A.Kholdeeva, M.N.Timofeeva, G.M.Maksi-
mov, R.I. Maksimovskaya, W.A. Neiwert, C.L. Hill,
Inorg. Chem.
2005, 44, 666–672.
[4] C.Boglio, G.Lenoble, C.Duhayon, B.Hasenknopf, R.Thouvenot,
C.Zhang, RC. .Howell, BP..Burton-Pye, LC. .Francesconi, E.
Lacôte, S.Thorimbert, M.Malacria, C.Afonso, J-.C.Tabet,
Chem. 2006, 45, 1389–1398.
Inorg.
General procedure
(0.5 mmol, 1 equiv) and the silyl enol ether (0.5 mmol, 1 equiv) were
added to a solution of TBA5K[a1-Hf(H2O)nP2W17O61] or TBA3.7K0.3[a-
1 (GP1)—Mannich-type reactions: The imine
[5] C.Boglio, G.Lemire, B.Hasenknopf, S.Thorimbert, E.Lacôte, M.
Malacria, Angew. Chem. 2006, 118, 3402–3405; Angew. Chem. Int.
Ed. 2006, 45, 3324–3327; our approach is conceptually different
from previous reports involving Lewis acid catalysis by cationic met-
allic counterions (see for example references [17,18]).
[6] R.D.Shannon, Acta Crystallogr. Sect. A 1976, 32, 751–767.
[7] A.F.Holleman, N.Wiberg in Inorganic Chemistry, Academic Press,
Berlin, New York, 2001, p.1338.
A
N
ACHTREUNG
Hf(OH)PW11O39] (20 mol%, 0.1 mmol) in CH3CN (3 mL).After comple-
tion of the reaction (unless otherwise noted), a solution of acetone/etha-
nol (1:1) (6 mL) was added, followed by diethyl ether (60 mL).The white
precipitate (catalyst) was centrifuged and separated from the reaction
products.The remaining organics were concentrated under reduced pres-
sure.The residue was purified by flash column chromatography (pen-
tane/ethyl acetate 95:5) to afford the desired b-amino ketones as unse-
parable mixtures of the two diastereomers.
[8] a) K.Murata, S.Ikeda, Anal. Chim. Acta 1983, 151, 29–38; b) T.Fu-
kumoto, K.Murata, S.Ikeda,
Anal. Chem. 1984, 56, 929–932;
c) H.W.Roesky, R.Siefken, Z. Anorg. Allg. Chem. 1998, 624, 171–
General procedure 2 (GP2)—aldol reactions: The aldehyde (0.5 mmol,
1 equiv) and the silyl enol ether (0.75 mmol, 1.5 equiv) were added to a
172; d) CN. .Kato, A.Shinora, K.Hayashi, K.Nomiya,
Inorg.
Chem. 2006, 45, 8108–8119; e) Y.Hou, X.Fang, C.L.Hill,
Abstracts
solution of TBA5K
A
G
N
of Papers, 232nd ACS National Meeting, San Francisco, 2006, INOR-
815.
W11O39] (20 mol%, 0.1 mmol) in CH3CN (3 mL).After completion of the
reaction, a solution of acetone/ethanol (1:1; 6 mL) was added followed
by diethyl ether (60 mL).The white precipitate (catalyst) was centrifuged
and separated from the reaction products.The organics were concentrat-
ed in vacuo.The crude mixture was dissolved in dichloromethane (2 mL)
and a 1m solution of HCl in diethyl ether (0.2 mL) was added. After
10 min, the solvent was evaporated under reduced pressure.The crude
mixture was dissolved in dichloromethane and washed with aqueous satu-
rated sodium hydrogenocarbonate and brine, dried over MgSO4, filtered,
and concentrated.The residue was purified by flash column chromatogra-
phy to afford the desired products.
[9] For hafnium salts-catalyzed reactions, see: a) K.Suzuki, H.Maeta,
T.Matsumoto, G.Tsuchihashi,
3574; b) P.C.Mçhring, N.J.Coville, J. Organomet. Chem. 1994, 479,
1; c) T.Harada, T.Ohno, S.Kobayashi, T.Mukaiyama, Synthesis
Tetrahedron Lett. 1988, 29, 3571–
1991, 1216–1220; d) S.Kobayashi, S.Iwamoto, S.Nagayama, Synlett
1997, 1099–1101.
[10] See Supporting Information for characterization of the new polyox-
ometallic compounds.
[11] Q.Lunyu, W.Shouguo, P.Jun, C.Yaguang, W.Guang,
Polyhedron
1992, 11, 2645–2649.
General procedure 3 (GP3)—imino Diels–Alder reactions: The imine
(0.5 mmol, 1 equiv) and diene or enol ether (0.75 mmol, 1.5 equiv) were
[12] O.A. Kholdeeva, G.M. Maksimov, R.I. Maksimovskaya, M.P.
Vanina, T.A. Trubitsina, D.Y. Naumov, B.A. Kolesov, N.S. Anto-
nova, J.J. Carbꢂ , J.M. Poblet, Inorg. Chem. 2006, 45, 7224–7234.
[13] C.R.Mayer, C.Roch-Marchal, H.Lavanant, R.Thouvenot, N.Selli-
er, J.-C. Blais, F. SØcheresse, Chem. Eur. J. 2004, 10, 5517–5523.
[14] A similar reactivity of Ti-substituted Keggin POMs has been report-
added to
a
solution of the catalyst TBA5K
G
N
(10 mol%, 0.05 mmol, 280 mg) in CH3CN (3 mL).After completion of
the reaction, a solution of acetone/ethanol (v/v; 1:1, 6 mL) was added fol-
lowed by diethyl ether (60 mL).The white precipitate (catalyst) was cen-
trifuged and separated from the reaction products.The organics were
concentrated under reduced pressure.The residue was purified by flash
column chromatography to afford the desired cyclic adducts.
ed: W.H. Knoth, P.J. Domaille, D.C. Roe,
198–201.
Inorg. Chem. 1983, 22,
[15] a) J.-P. Ciabrini, R. Contant, J. Chem. Res. (M) 1993, 2720–2744;
b) C.Zhang, RC. .Howell, Q-H. .Luo, HL. .Fieselmann, LJ..
Todaro, L.C.Francesconi, Inorg. Chem. 2005, 44, 3569–3578.
[16] For related observations with hygroscopic Lewis acids (Zr), see:
a) S.Kobayashi, T.Ogino, H.Shimizu, S.Ishikawa, T.Hamada, K.
Manabe, Org. Lett. 2005, 7, 4729–4731; b) K.Saruhashi, S.Kobaya-
shi, J. Am. Chem. Soc. 2006, 128, 11232–11235; for a more general
review: c) S.Kobayashi, C.Ogawa, Chem. Eur. J. 2006, 12, 5954–
5960.
Acknowledgements
This work was supported by UPMC, CNRS, IUF (of whom M.M. is a
senior member), and ANR (grant JC05 41806 to E.L., S.T., and B.H.,
postdoctoral fellowship to P.R.). C.B. and K.M. thank the Ministre de la
recherche for fellowships.We thank Dr.RenØ Thouvenot (UPMC) for
the 183W NMR analysis.We are indebted to Prof.Pierre Gouzerh
(UPMC) and Prof.Mukund P.Sibi (NDSU, Fargo) for invaluable sugges-
tions and advice.
[17] I.V. Kozhevnikov in Catalysts for Fine Chemical Synthesis Vol.2,
Catalysis by Polyoxometalates, Wiley, Chichester, 2002, pp.80–89.
[18] H.Firouzabadi, N.Iranpoor, F.Nowrouzi,
10843–10850.
Tetrahedron 2004, 60,
[19] R.Contant, Inorg. Synth. 1990, 27, 104–111.
[20] R.Contant, Can. J. Chem. 1987, 65, 568–573.
[1] a) M.Misono, Catal. Today 2005, 100, 95–100; b) “Applications of
Polyoxometalates in Homogeneous Catalysis”: R.Neumann, NATO
Sci. Ser. II 2003, 98, 327–349; c) “Heterogeneous Catalysis by Het-
eropoly Compounds”: I.V.Kozhevnikov, NATO Sci. Ser. II 2003, 98,
351–380.
Received: January 3, 2007
Published online: March 15, 2007
5432
ꢀ 2007 Wiley-VCH Verlag GmbH & Co.KGaA, Weinheim
Chem. Eur. J. 2007, 13, 5426 – 5432