1
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Q.-H. Fan et al. / Tetrahedron: Asymmetry 12 (2001) 1241–1247
OH) in DMAc (5 mL) was then added. The mixture
was stirred at 40–50°C for a further 8 h. To this
solution was slowly added diethyl ether (50 mL) with
vigorous stirring. The precipitated polymer was filtered
and washed with cold methanol and diethyl ether, then
dried under vacuum to give MeO-PEG-supported
CD Cl ): 55.15, 55.37. Molecular weight (M )=10540
2 2 w
(on the basis of polystyrene calibration); amount of
Ru(BINAP)(acac) moieties=16.0 g per 100 g polymer
2
1
(determined by H NMR).
3.6. General procedure for the hydrogenation of 2-(6%-
methoxy-2%-naphthyl)propenoic acid 5 catalyzed by cat-
alyst 3
1
BINAP ligand 2 (0.97 g, 98%). H NMR (400 MHz,
CD Cl ): 3.27–3.80 (polyethylene glycol peaks), 6.79 (t,
2
2
J=7.80 Hz, 2H), 7.02–7.20 (m, 19.2H), 7.45 (t, 2H)
In a glovebox under a nitrogen atmosphere, a 45 mL
glass-lined stainless steel reactor with a magnetic stir-
ring bar was charged with catalyst 3 (3.66 mg), sub-
31
7
.60 (s, 2H), 8.09–8.16 (m, 6); P NMR (160 MHz,
CD Cl ): −16.82. Molecular weight (M )=10540 (on
2
2
w
the basis of polystyrene calibration); amount of BINAP
strate 5 (15 mg), NEt (8 mL) and MeOH (2.5 mL). The
3
1
moieties=5.65 g per 100 g polymer (determined by H
reactor was closed and pressurized with H to 1000 psi.
2
NMR).
The mixture was stirred with a magnetic stirrer under
H pressure at 25°C for 2 h. The H gas pressure was
2
2
3
.3. MeO-PEG-supported [RuCl(binap)(cymene)]Cl 3
vented and the products were analyzed by HPLC using
−3
a
SUMICHIRAL OA-2500 column: 6×10
4
M
R
A mixture of MeO-PEG-supported BINAP 2 (500 mg,
8 mg, 0.045 mmol BINAP) and [RuCl (cymene)]2
NH OAc of MeOH solution; flow rate=1.2 mL/min; t
2
(R)-enantiomer=14.63, tR (S)-enantiomer=17.33, and
tR 5=14.82 min.
2
(
13.5 mg, 0.022 mmol) in dichloromethane/MeOH (1/1,
v/v, 10 mL) was magnetically stirred under a nitrogen
atmosphere at 50–60°C for 40 min. After cooling to
room temperature, the solvent was removed under
reduced pressure to give pale yellow catalyst 3. This
catalyst was used in the asymmetric hydrogenation
3.7. Asymmetric hydrogenation of 5 catalyzed by cata-
lyst 3 illustrating the recycle of the MeO-PEG-sup-
ported Ru(BINAP) catalysts
31
reactions without further purification. P NMR (160
In a glovebox under a nitrogen atmosphere, a 45 mL
glass-lined stainless steel reactor with a magnetic stir-
ring bar was charged with catalyst 3 (7.32 mg), sub-
MHz, CDCl ): 25.1 (d, J=61.4 Hz), 38.8 (d, J=62.9
3
Hz).
strate 5 (30 mg), NEt (16 mL) and MeOH (4 mL). The
3
3
.4. Ru(5,5%-Diamino BINAP)(acac) 1a
autoclave was pressurized with hydrogen to 1800 psi
and the mixture was stirred at 0°C for 8 h. The auto-
clave was depressurized, and most of the methanol was
then removed under reduced pressure. The residue was
treated with diethyl ether (20 mL). The precipitated
polymeric catalyst was collected by filtration for re-use
in the next reaction. The filtrate was used for the
determination of e.e. and conversion of the product.
2
A 50 mL flask equipped with a condenser and a stirring
bar was charged with of 5,5%-diamino (R)-BINAP 1 (0.5
g, 0.767 mmol), Ru(acac) (0.30 g, 0.754 mmol), Zn
3
dust (1 g) and degassed EtOH (20 mL) under a nitrogen
atmosphere. The mixture was heated under reflux
overnight. Most of the solvent was removed under
reduced pressure and the evaporation residue was
extracted with CH Cl (three times) the combined
3.8. (3R,4R)-N-(4-Carboxybutanoyl)-3,4-bis-
(diphenylphosphino)-pyrrolidine 8
2
2
brownish–yellow organic extract was concentrated
1
under reduced pressure to give 1a (695 mg, 98%). H
NMR (400 MHz, CDCl ): 1.27 (s, 3H), 1.54 (d, J=5.62
To a solution of 7 in CH Cl2 was added succinic
3
2
Hz, 6H), 1.84 (s, 3H), 3.90 (s, 4H), 4.79 (s, 1H), 5.04 (s,
anhydride (2–3 equivalents) and the mixture was stirred
1
1
5
H), 6.06 (d, J=8.61 Hz, 1H), 6.13 (d, J=8.58 Hz,
H), 6.36–7.70 (m, 28H); P NMR (160 MHz, CDCl3):
5.4(s), 55.1(s).
overnight. After washing with water, the CH Cl phase
2
2
31
was dried over anhydrous MgSO . The crude product
4
was further purified by column chromatography to give
1
8
(more than 95% yield). H NMR (400 MHz, CDCl ):
3
3.5. MeO-PEG-supported Ru(BINAP)(acac) 4
2.42–2.45 (m, 2H), 2.61–2.65 (m, 2H), 2.89 (m, 1H),
.98 (m, 1H), 3.34 (t, J=11.89 Hz, 1H), 3.71 (t, J=
12.79 Hz, 1H), 3.86–3.89 (m, 2H), 7.16–7.18 (m, 4H),
2
1
To a cooled solution of terephthaloyl chloride (30 mg,
.148 mmol) and dried DMAc (2 mL), a solution of 1a
100 mg, 0.104 mmol) in dried DMAc (2 mL) contain-
31
0
7.24–7.26 (m, 4H), 7.31–7.38 (m, 12H); P NMR (160
(
MHz, CDCl ): −12.14, −12.69.
3
ing NEt (50 mL, 0.35 mmol) was added dropwise with
3
stirring. The reaction mixture was stirred at rt for
another 60 min under a nitrogen atmosphere. A solu-
tion of MeO-PEG-OH (Mn=5000, 430 mg, 0.086
mmol) in DMAc (4 mL) was then added. The solution
was stirred at rt for 30 min, then heated to 40–50°C and
stirred for a further 8 h. To this solution was slowly
added diethyl ether (25 mL) with vigorous stirring. The
precipitated polymer was filtered and washed with cold
methanol and diethyl ether, then dried in vacuo to give
3.9. MeO-PEG-supported Pyrphos 9
DCC (55 mg, 0.267 mmol) was added to a mixture of
MeO-PEG-OH (450 mg, 0.09 mmol), DMAP (10 mg,
0.082 mmol), and 8 (50 mg, 0.093 mmol) in CH Cl .
2
2
The mixture was stirred overnight and the urea precipi-
tate was removed by filtration through Celite. To this
solution was slowly added cold dried diethyl ether (25
mL) with vigorous stirring. The precipitated polymer
was filtered and washed with cold methanol and diethyl
3
1
yellow product 4 (540 mg, 98%). P NMR (160 MHz,
Fan, Qing-Hua
