Angewandte
Chemie
occurs slowly during catalysis, as proven by the fact that
subsequently added acetophenone (up to three times) under-
goes quantitative conversion. Therefore, catalyst 4 can be
used in a very low amount (0.01 mol%), in contrast to the
most active ruthenium catalysts which undergo rapid leach-
ing. Since chiral ligands related to 2-(aminomethyl)pyridine
have been recently employed in asymmetric hydrogen-trans-
[3] a) W. A. Herrmann, C. Brossmer, C.-P. Reisinger, T. H. Rier-
meier, K. Öfele, M. Beller, Chem.Eur.J.
1997, 3, 1357;
b) V. P. W. Böhm, W. A. Herrmann, Chem.Eur.J.
2001, 7,
4191; c) J. Dupont, M. Pfeffer, J. Spencer, Eur.J.Inorg.Chem.
2001, 1917.
[
[
4] T. Naota, H. Takaya, S.-I. Murahashi, Chem.Rev. 1998, 98, 2599.
5] a) L. N. Lewis, J.Am.Chem.Soc. 1986, 108, 743; b) L. N. Lewis,
J. F. Smith, J.Am.Chem.Soc. 1986, 108, 2728.
[
18]
fer reactions with ruthenium, their use with 2 holds promise
for obtaining high-speed enantioselective catalysts.
[6] W. Baratta, E. Herdtweck, P. Rigo, Angew.Chem. 1999, 111,
1733; Angew.Chem.Int.Ed. 1999, 38, 1629.
[
7] W. Baratta, S. Stoccoro, A. Doppiu, E. Herdtweck, A. Zucca, P.
In summary, the d-agostic compound 2, prepared from the
Rigo, Angew.Chem. 2003, 115, 109; Angew.Chem.Int.Ed. 2003,
1
4-electron species 1, gives access to the synthesis of a new
class of cyclometalated derivatives. Complex 4, prepared from
and 2-(aminomethyl)pyridine, is one of the most active
42, 105.
[
8] W. Baratta, E. Herdtweck, P. Martinuzzi, P. Rigo, Organo-
metallics 2001, 20, 305.
2
catalysts for the reduction of ketones in 2-propanol by a
hydrogen-transfer reaction. The presence of a robust cyclo-
metalated metal–carbon bond apparently allows the forma-
tion of long-living catalytic species, which may have great
potential for use in other catalytic reactions and synthetic
methods.
[
9] a) G. Zassinovich, G. Mestroni, S. Gladiali, Chem.Rev. 1992, 92,
1051; b) R. Noyori, S. Hashiguchi, Acc.Chem.Res. 1997, 30, 97;
c) J. E. Bäckvall, J.Organomet.Chem.
2002, 652, 105; d) S.
Gladiali, G. Mestroni in Transition Metals for Organic Synthesis,
Vol.2 (Eds.: M. Beller, C. Bolm), Wiley-VCH, Weinheim, 1998,
p. 97.
1
[
[
10] 2: H NMR (200.1 MHz, CDCl , 208C, TMS): d = 7.8–6.9 (m,
3
26H; aromatic protons), 3.48 (d, J(H,H) = 13.4 Hz, 1H;
RuCH ), 3.29 (dd, J(H,H) = 13.4 Hz, J(H,P) = 5.4 Hz, 1H;
2
3
1
1
Experimental Section
CH ), 1.76 (s, 3H; CH ), 1.64 ppm (s, 6H; CH ); P{ H} NMR
2 3 3
2
: Triethylamine (1.90 mL, 13.6 mmol) and formaldehyde (1.00 mL,
(81.0 MHz, CDCl , 208C, H PO ): d = 53.7 (d, J(P,P) = 301 Hz;
3 3 4
3
7% solution in water, 13.4 mmol) were added to a suspension of 1
PC), 32.8 ppm (d, J(P,P) = 301 Hz; P); IR (nujol): n˜ (CO) =
À1
(2.00 g, 2.66 mmol) in ethanol (40 mL) under argon. The mixture was
1923 cm ; elemental analysis (%) calcd for C H ClOP Ru: C
4
1
37
2
refluxed for 2 h and then concentrated to half its volume. After
filtration, the product was dried under reduced pressure. Yield: 1.60 g
66.2, H 5.0; found: C 65.9, H 5.0.
11] Crystal structure analysis of 2, C H ClOP Ru, M = 744.17,
4
1
37
2
r
(81%).
monoclinic, space group P2 , a = 9.502(3), b = 9.974(3), c =
1
3
4
: 2-(Aminomethyl)pyridine (90 mL, 0.87 mmol) and CaCO3
19.771(6) ,
1
2
b = 111.98(2)8, V= 1737.5(9) , Z = 2, 1calcd
.422 gcm , m(MoKa) = 0.652 mm , F(000) = 764, 2.16 < q <
9.948. Final R1 = 0.0497, wR2 = 0.1454, S = 1.045 for 412
=
À3
À1
(39 mg, 0.39 mmol) were added to
a solution of 2 (535 mg,
0
.72 mmol) in dichloromethane (10 mL) under argon. The suspension
was heated at reflux overnight, filtered, and concentrated. The
product was precipitated with diethyl ether, filtered, and dried under
reduced pressure. Yield: 308 mg (76%).
Typical procedure for the catalytic hydrogen-transfer reaction:
Complex 4 (2.8 mg, 5.0 mmol) was dissolved in a 0.04m solution of
NaOH in 2-propanol (5 mL). The ketone (2 mmol) was dissolved in 2-
propanol (19 mL) and the solution was heated to reflux under argon.
Addition of the solution of 4 (1 mL) resulted in the immediate
reduction of the ketone and the yield was determined by GC analysis
parameters and 9754 reflections, 9401 unique (Rint = 0.0393),
max positive and negative peaks in DF map 0.691 and
À3
À0.821 e . Data were were collected at 150(2) K on a
Nonius DIP-1030H system with Mo radiation (l = 0.71073 ).
Ka
[
12] The molecular structure of 3 is related to that of 2 with two
PMePh2 ligands trans to the cyclometalated phosphane.
2 3 r
3·0.5Et O: C49H49ClO1.50P Ru, M = 891.31, monoclinic, space
group C2/c, a = 21.735(5), b = 10.385(3), c = 37.589(6) , b =
3
À3
94.50(2)8,
V= 8458(3) ,
Z = 8,
1calcd = 1.400 gcm ,
(ketone/4/NaOH = 2000:1:40; ketone 0.1m).
À1
m(MoKa) = 0.586 mm , F(000) = 3688, 2.17 < q < 27.108. Final
R1 = 0.0462, wR2 = 0.1459, S = 1.060 for 506 parameters and
Received: March 5, 2004 [Z54199]
1
0511 reflections, 6096 unique (R(int) = 0.0470), residuals in DF
À3
map 0.680, À0.778 e . Data were collected at 150(2) K on a
Nonius DIP-1030H system with MoKa radiation (l = 0.71073 ).
CCDC-224572 (2) and CCDC-224573 (3) contain the supple-
mentary crystallographic data for this paper. These data can be
obtained free of charge via www.ccdc.cam.ac.uk/conts/retrie-
ving.html (or from the Cambridge Crystallographic Data Centre,
12 Union Road, Cambridge CB21EZ, UK; fax: (+ 44)1223-336-
Keywords: cyclometalation · homogeneous catalysis ·
.
noncovalent interactions · P ligands · ruthenium
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1
[13] 4: H NMR (200.1 MHz, CDCl
, 208C, TMS): d = 9.01 (d,
N), 7.92–6.88 (m, 16H; aromatic
protons), 4.35 (d pseudot, J(H,H) = 16.1 Hz, J(H,H) = 4.4 Hz,
1H; CH N), 4.01 (d pseudot, J(H,H) = 16.2 Hz, J(H,H) =
6.4 Hz, 1H; CH N), 3.05 (m, 1H; NH ), 2.95 (d, J(H,H) =
14.9 Hz, 1H; RuCH ), 2.15 (d, J(H,H) = 14.8 Hz, 1H; RuCH ),
1.85 (m, 1H; NH ), 1.76 ppm (s, 3H; CH ); C{ H} NMR
(50.3 MHz, CDCl , 208C, TMS): d = 205.4 (d, J(C,P) = 19.1 Hz;
CO), 164.1 (d, J(C,P) = 31.8 Hz; CCH Ru), 159.7 (s; NCCH ),
152.3 (s; o-C N), 141.3 (s, CCCH ), 136.4 (s; p-C N), 135.1–
120.9 (aromatic carbon atoms), 48.8 (d, J(C,P) = 2.9 Hz;
CH NH ), 23.1 (d, J(C,P) = 3.6 Hz; RuCH ), 22.3 ppm (d,
J(C,P) = 3.8 Hz; CH ); P{ H} NMR (81.0 MHz, CDCl , 208C,
3
J(H,H) = 5.6 Hz, 1H; o-C H
5 4
2
2
2
2
2
1
3
1
2
3
1
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2
2
H
5
H
5 4
4
3
2
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2] a) A. D. Ryabov, Chem.Rev. 1990, 90, 403; b) I. Omae, Coord.
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2
2
2
3
1
1
3
3
Angew. Chem. Int. Ed. 2004, 43, 3584 –3588
ꢀ 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
3587