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Z. Guo et al. / Tetrahedron: Asymmetry 17 (2006) 468–473
The acid chloride 9 THF solution was added dropwise
to this solution. The resulting solution was stirred at rt
for 30 min. Saturated sodium bicarbonate was added
and the aqueous layer extracted three times with CHCl3.
The combined organic layer was dried over Na2SO4 and
solvent removed in vacuo. The diastereomers were
separated from other impurities by column chromato-
graphy (petroleum ether/EtOAc = 20:1). This procedure
provided an oil mixture of 5A and 5B (520 mg,
1.0 mmol, 52% yield), which partially solidified on
standing. The mixture of diastereomers 5A and 5B
was separated by silica gel column chromatography
(petroleum ether/CH2Cl2 from 1:5 to 0:100) to give
diastereomer 5A (234 mg, 0.47 mmol, 45% yield) and
5B (244 mg, 0.49 mmol, 47% yield). All spectroscopic
and physical data were in accordance with previous
literature.11
4.4. Synthesis of (1R,2R,10R)-1,10-bis(diphenylphosphin-
oxy)-2,20-spirobiindane 7 [(R)-SpiroBIP]
Diol 6A (100 mg, 0.4 mmol) and DMAP (36 mg,
0.3 mmol) were dissolved into 20 mL of THF under an
argon atmosphere and cooled to 0 °C with an ice bath.
A
solution of chlorodiphenylphosphine (0.16 mL,
0.9 mmol) in THF (1 mL) was added dropwise and fol-
lowed by the addition of triethylamine (0.50 mL,
3.6 mmol). The reaction mixture was allowed to warm
to ambient temperature and stirred for 30 min. Filtra-
tion of triethylammonium chloride followed by flash
column chromatography on basic silica gel (toluene
as eluent) to give a white solid 7 (120 mg, 0.2 mmol,
20
48% yield). mp 113–114 °C; ½aꢁD ¼ þ8:4 (c 0.154,
CHCl3); 31P NMR (CDCl3, 75 MHz) d (ppm) 103.1 (s);
1H NMR (CDCl3, 300 MHz) d (ppm) 7.37–7.08 (m,
14H), 5.52 (d, 1H, J = 5.4 Hz), 3.20 (d, 1H, J =
14.7 Hz), 2.28 (d, 1H, J = 14.7 Hz). 13C NMR (CDCl3,
75 MHz) d (ppm) 144.2, 143.3 (d, J = 81.9 Hz), 142.6
(d, J = 58.2 Hz), 142.1, 131.1 (d, J = 39.6 Hz), 130.2,
130.0, 129.9, 129.7, 128.7, 128.4, 127.9, 127.8, 127.6,
127.5, 126.4, 125.9, 125.2, 85.5 (d, J = 67.7 Hz), 63.4,
41.6. HRESI-MS (positive ion) C41H34NaO2P2
([M+Na]+) requires 643.1920. Found 643.1926.
Diastereomer 5A: 1H NMR (CDCl3, 300 MHz) d (ppm)
7.51–7.17 (m, 13H), 6.10 (s, 1H), 5.19 (s, 1H), 5.06 (d,
1H, J = 3.2 Hz), 3.16 (d, 1H, J = 10.2 Hz), 3.10
(d, 1H, J = 10.2 Hz), 2.50 (d, 1H, J = 12.0 Hz), 2.44
(d, 1H, J = 12.0 Hz), 2.03 (d, 1H, J = 3.2 Hz), 0.82
20
(s, 9H), ꢀ0.06 (s, 3H), ꢀ0.14 (s, 3H). ½aꢁD ¼ ꢀ84:5
(c 10.6, chloroform).
Diastereomer 5B: 1H NMR (CDCl3, 300 MHz) d (ppm)
7.65 (dd, 1H, J = 7.3 and 1.3 Hz), 7.51–7.17 (m, 12H),
6.13 (s, 1H), 5.16 (s, 1H), 4.78 (d, 1H, J = 3.8 Hz),
3.14 (d, 1H, J = 11.2 Hz), 3.09 (d, 1H, J = 11.2 Hz),
2.43 (d, 1H, J = 9.8 Hz), 2.38 (d, 1H, J = 9.8 Hz), 1.55
4.5. Typical procedures for the preparation of the catalyst
and for an asymmetric catalytic hydrogenation
[Rh(COD)2]BF4 (2.5 mg, 6.2 lmol) and (R)-SpiroBIP 7
(4.6 mg, 7.4 lmol) were dissolved in degassed toluene
(0.30 mL) and degassed MeOH (0.30 mL) and stirred
for 20 min to form a solution of [Rh(COD)(R-Spiro-
BIP)]BF4 catalyst for the asymmetric hydrogenation.
Then 0.6 mmol of substrate, the catalyst solution pre-
pared above and 4 mL of degassed MeOH under argon
atmosphere was added into a 50 mL stainless steel auto-
clave. The vessel was charged with H2 with a final pres-
sure of 5 atm. The reaction was carried out at room
temperature for 24 h. The resulting solution was passed
through a short silica gel column to remove the catalyst.
The ee value and conversion of the product were deter-
mined from the crude reaction mixture. Free amino
acids were converted to corresponding methyl ester for
the determination of ee by chiral GC (CP-Chirasil-
DXE column for the analysis of 2-acetamidopropionic
acid methyl ester and Chirasil-L-Val column for other
products).
(d, 1H, J = 3.4 Hz), 0.90 (s, 9H), 0.10 (s, 3H), ꢀ0.03
20
(s, 3H). ½aꢁD ¼ þ114:0 (c 8.4, chloroform).
Mono esters’ de values were determined by HPLC
i
((Chiralpak AS column, PrOH/Hex(3/97), 0.25 mL/
min at 254 nm) t5A = 3.12 min, t5B = 6.03 min).
De5A P99% and De5B P99%.
4.3. Preparation of diol (1R,2R,10R)-2,20-spirobiindane-
1,10-diol (ꢀ)-6A and (1S,2S,10S)-2,20-spirobiindane-1,10-
diol (+)-6B
To a solution of compound 5A or 5B (1.0 g, 2.0 mmol) in
EtOH (200 mL) was added 10% sodium hydroxide
(100 mL) at room temperature. Slow formation of a white
precipitate was observed. After stirring for 20 min, the
reaction mixture was extracted with CHCl3 (250 mL).
The organic layer was dried over Na2SO4 and solvent
was removed in vacuo. The residue was recrystallization
from CHCl3 to provided a white solid 6A (410 mg,
1.6 mmol, 82% yield, P99% ee) or 6B (425 mg, 1.7 mmol,
85% yield, P99% ee). Diols’ ee values were determined by
HPLC ((Chiralpak AS column, iPrOH/Hex(15/85),
0.50 mL/min at 254 nm) t6A = 7.57 min, t6B = 9.90 min).
All the spectroscopic and physical data were identical to
that in the literature.11 1H NMR (CDCl3, 300 MHz) d
(ppm) 7.49–7.45 (m, 2H), 7.32–7.21 (m, 6H), 5.18 (s,
2H), 3.16 (d, 2H, J = 15.5 Hz), 2.95 (br s, 2H), 2.55 (d,
Acknowledgement
We are grateful for financial support from National
Natural Science Foundation of China (Project
20502025).
References
2H, J = 15.5 Hz). (ꢀ)-6A: mp 243–244 °C (dec).
1. Tang, W.; Zhang, X. Chem. Rev. 2003, 103, 3029.
2. (a) Chan, A. S. C.; Hu, W.-H.; Pai, C.-C. J. Am. Chem.
Soc. 1997, 119, 9570; (b) Hu, W.-H.; Yan, M.; Lau, C.-P.;
Yang, S.-M.; Chan, A. S. C. Tetrahedron Lett. 1999, 40,
20
½aꢁD ¼ ꢀ50:3 (c 0.056, Sure/Seal TM acetone). (+)-6B:
20
mp 236–237 °C (dec). ½aꢁD ¼ þ42:5 (c 0.084, 1 dm,
Sure/Seal TM acetone).