COMMUNICATIONS
catalyst. The continuous decrease in selectivity in consecutive
runs may therefore be ascribed to an increasing contribution
of the highly active, but unselective, leached rhodium carbon-
4 was prepared analogously to 3 from 1 (100 mg, 0.131 mmol) and [MCM-
[
19]
4
1]-(CH
tion: 2q100 2.2658, a 45.0 ; P CP-MAS NMR (162 MHz): d 18.75
br s, J(Rh,P) unresolved).
endo-5: mixture of
CH PPh (44 mg, 0.039 mmol) in toluene (20 mL) and glacial acetic acid
2
)
2
PPh
2
(1.0 g, ca. 0.6 mmol PPh
2
); yield 1.034 g; X-ray diffrac-
31
(
[
17]
yl species
to the overall conversion, corresponding to a
A
5 9 7 8 12
1 (30 mg, 0.039 mmol) and (c-C H ) Si O -
simultaneous decrease in the concentration of the immobi-
lized species. However, the nature of the support had a
dramatic effect on the degree of leaching: while catalyst 3,
immobilized on amorphous silica, had lost almost all of its
initial activity after only four catalytic runs, the respective
drop in activity was less pronounced for catalyst 4, with the
catalytic complex anchored inside the mesopores of MCM-41.
Furthermore, an increase in pressure from 30 to 60 bar
resulted in an almost negligible drop in catalytic activity for
catalyst 4 during recycling.
(
2
)
2
2
(2 mL) was heated at 608C for 12 h. The solvent was removed in vacuo, and
the residue was purified by chromatography on silica gel with toluene/
CH COOH (10/1) as eluent. Collection of the first pink band and
3
subsequent solvent removal in vacuo afforded a mixture of diastereomers
of 5. The major endo-component was separated by repeated chromatog-
2 2 3
raphy on silica gel with hexane/CH Cl /CH COOH (70/30/2). Suitable
crystals of endo-5 for X-ray analysis were grown from CH
2
Cl
2
/hexane; yield
Si), 0.42
), 1.37 ± 1.79 (m, 56H, CH
, bridging acetate), 2.20 (m,
1
3
3 mg (48%); H NMR (400 MHz, CDCl
3
): d � 0.54 (m, 1H, CH
2
(
m, 1H, CH
2
Si), 0.85 ± 1.02 (m, 7H, CH, c-C
5
H
9
2
,
c-C
5
H
9
), 2.06 (m, 1H, CH
2
P), 2.14 (s, 6H, CH
3
3
1
H, CH
2
P), 6.43 (t, J(H,H) 8.52 Hz, 1H, aromatic CH), 6.66 (t,
Catalyst 4 was also employed in the hydroformylation of
3
J(H,H) 7.49 Hz, 1H, aromatic CH), 6.70 (t,
3
J(H,H) 7.73 Hz, 1H,
3
1
-decene. The chemoselectivity in favor of aldehyde products
aromatic CH), 6.76 ± 6.87 (m, 4H, aromatic CH), 6.96 (td, J(H,H) 7.43,
1.76 Hz, 2H, aromatic CH), 7.08 ± 7.18 (m, 3H, aromatic CH), 7.25 ± 7.35 (m,
exhibited by 4 is in all subsequent runs significantly lower for
this olefin than for styrene hydroformylation. The fraction of
the hydrogenated side-product, n-decane, increases steadily at
the expense of hydrocarbonylated products in subsequent
catalytic runs, while the amount of isomerized decene by-
products is not changed significantly. Simultaneously, a steady
increase in regioselectivity within the aldehyde fraction
towards the linear product n-undecanal with each consecutive
run is observed, as expressed by the rise of the linear:
branched aldehyde ratio (n:b) from 1.52:1 (run 1) to 2.13:1
8
H, aromatic CH), 7.51 ± 7.59 (m, 2H, aromatic CH), 8.16 ± 8.22 (m, 1H,
31
1
1
aromatic CH); P{ H} NMR (101 MHz, CDCl
3
1
): d 16.14 (dd, J(Rh,P)
2
2
1
66.98, J(Rh,P) 7.35 Hz, P2), 19.93 (dd, J(Rh,P) 173.14, J(Rh,P)
13
1
7.95 Hz, P1); C{ H} NMR (100 MHz, CDCl
3
): d 6.40 (CH
), 23.46 (CH
), 121.30 (d, J(C,P)
.8 Hz, aromatic CH), 121.85 (d, J(C,P) 9.1 Hz, aromatic CH), 127.01 (d,
2
Si), 21.60
1
(
d, CH
2
P, J(P,C) 28.9 Hz), 22.26 ± 22.70 (CH, c-C
5
H
9
3
,
2 5 9
bridging acetate), 27.03, 27.31, 27.41 (all CH , c-C H
8
2
C, J(C,P) 9.7 Hz, aromatic CH), 127.55 (d, 2C, J(C,P) 9.3 Hz,
aromatic CH), 127.73 (d, 2C, J(C,P) 8.8 Hz, aromatic CH), 128.33,
130.27, 133.06 (all s, aromatic CH), 128.39 (d, 2C, J(C,P) 12.9 Hz,
aromatic CH), 128.91 (d, 2C, J(C,P) 7.2 Hz, aromatic CH), 131.03 (d, 2C,
J(C,P) 8.4 Hz, aromatic CH), 133.11 (d, 2C, J(C,P) 9.0 Hz, aromatic
CH), 133.58 (d, 2C, J(C,P) 9.1 Hz, aromatic CH), 136.51 (d, J(C,P)
(run 4). The low level of regioselectivity for the linear
aldehyde product in the hydroformylation of 1-decene is
indicative of a reactive site with a low degree of steric
1
5.8 Hz, aromatic CH), 137.91 (d, J(C,P) 12.9 Hz, aromatic CH), 132.70,
133.81, 134.26, 138.21, 138.63 (all s, aromatic C), 143.95, 147.44 (all m, RhC),
179.33 (s, COO, terminal), 181.10, 181.24 (all s, COO, bridging).
[
1]
encumbrance.
Received: August 28, 2000
Revised: December 13, 2000 [Z15710]
Experimental Section
All reactions were carried out under an argon atmosphere in dry solvents
using standard Schlenk techniques unless stated otherwise.
[1] Latest comprehensive review: Rhodium Catalyzed Hydroformylation
(
Eds.: P. W. N. M. van Leeuwen, C. Claver), Kluver, Dordrecht, 2000.
[
2
0
SiO
2
]-(CH
008C, 250 m g
.325 mmol), and pyridine (77 mg, 0.975 mmol) in toluene (30 mL) was
2 2 2
) PPh : A mixture of fumed silica (5.0 g, vacuum-dried at
2
� 1
[18]
[2] a) Y. I. Yermakov, B. N. Kuznetsov, V. A. Zakharov, Catalysis by
Supported Complexes, Elsevier, Amsterdam, 1981; b) F. R. Hartley,
Supported Metal Complexes, Riedel, Dordrecht, 1985; c) Y. Iwasawa
in Tailored Metal Catalysts (Ed.: Y. Iwasawa), Riedel, Dordrecht,
1986, Chap. 1; d) V. A. Likholobov, B. L. Moroz in Handbook of
Heterogeneous Catalysis (Eds.: G. Ertl, H. Knözinger, J. Weitkamp),
Wiley-VCH, Weinheim, 1997, p. 2230.
3] a) K. G. Allum, R. D. Hancock, S. McKenzi, R. C. Pitkethly in
Proceedings of the Vth International Congress of Catalysis, Vol. 1,
Elsevier, Amsterdam, 1973, p. 477; b) H. Arai, J. Catal. 1978, 51, 135.
4] A. J. Sandee, L. A. van der Veen, J. N. H. Reek, P. C. J. Kramer, M.
Lutz, A. L. Spek, P. W. N. M. van Leeuwen, Angew. Chem. 1999, 111,
,
9.75 mmol SiOH ), Ph
2
P(CH
2
)
2
SiCl
3
(113 mg,
stirred at 258C for 12 h. The solid was filtered, washed with methanol
(
5
Ph).
250 mL) and diethyl ether (50 mL), and dried in vacuo at 808C; yield
.052 g; 3 P CP-MAS NMR (162 MHz): d � 9.95; IR: nÄ 1443 cm (P-
1
� 1
[
1
Me
MCM-41]-(CH
000 m g
2
)
2
PPh
2
: Siliceous MCM-41 (2.5 g, vacuum-dried at 2008C,
[
2
� 1
[18]
,
19.5 mmol SiOH
) was suspended in hexane (50 mL),
2
SiCl (0.034 mL, 0.28 mmol) was added at 08C and the mixture was
2
allowed to warm to ambient temperature and stirred for 1 h. The volatiles
were then removed in vacuo. The solid was suspended in toluene (50 mL).
Ph P(CH ) SiCl (695 mg, 2 mmol) was slowly added at 08C, and the
2 2 2 3
mixture was stirred at ambient temperature for 24 h. The released HCl was
then removed by heating the mixture under reflux in a stream of dry argon
for 2 h. The product was collected by filtration, washed with CH
3
2
1
[
3
428; Angew. Chem. Int. Ed. 1999, 38, 3231.
5] C. Claver, N. Ruiz, P. Lahuerta, E. Peris, Inorg. Chim. Acta 1995, 233,
61.
6] a) C. U. Pittman in Polymer-Supported Reactions in Organic Synthesis
Eds.: P. Hodge, D. C. Sherrington), Wiley, Chichester, 1980, Chap. 5;
[
[
1
2
Cl
2
(10 Â
0 mL) and dried in vacuo at 808C; yield 3.137 g; X-ray diffraction: 2q100
(
31
.2758, a 44.8 ; P CP-MAS NMR (162 MHz): d � 9.89; IR: nÄ
b) C. De-An, C. U. Pittman, J. Mol. Catal. 1983, 21, 405; c) G. A.
Korneeva, O. L. Butkova, L. I. Zvezdkina, N. A. Pritula, S. M. Loktev,
Y. I. Kogan in Homogeneous and Heterogeneous Catalysis (Eds.: Y. I.
Yermakov, V. A. Likholobov), VNU, Utrecht, 1986, p. 551.
�
1
440 cm (P-Ph).
3
0
2 2 2 2
: A mixture of 1 (35 mg, 0.046 mmol) and [SiO ]-(CH ) PPh (1.5 g, ca.
.1 mmol PPh
[19]
2
) in toluene (30 mL) was heated under reflux for 15 min.
Glacial acetic acid (10 mL) was added and heating was continued for
additional 1.5 h. The pink solid was collected by filtration and washed with
methanol (50 mL) and diethyl ether (20 mL), and dried in vacuo; yield
[7] a) C. T. Kresge, M. E. Leonowicz, W. J. Roth, J. C. Vartuli, J. S. Beck,
Nature 1992, 359, 710; b) T. Maschmeyer, Curr. Opin. Solid State
Mater. Sci. 1998, 3, 71; c) J. Y. Ying, C. P. Mehnert, M. S. Wong, Angew.
Chem. 1999, 111, 58; Angew. Chem. Int. Ed. 1999, 38, 56; d) J. M.
Thomas, Angew. Chem. 1999, 111, 3800; Angew. Chem. Int. Ed. 1999,
38, 3589.
1
.528 g. The filtrate did not contain any residual dinuclear rhodium
3
1
complex, indicating complete adsorption. P CP-MAS NMR (162 MHz):
d 18.87 (br s, J(Rh,P) unresolved).
Angew. Chem. Int. Ed. 2001, 40, No. 5
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2001
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957