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N. Ribeiro, K. Saigo / Tetrahedron: Asymmetry 20 (2009) 2704–2708
of 2 by a HPLC analysis. In the cases of 2d–f, they were converted to
the corresponding methyl esters by treatment with TMSCHN2 in a
mixture of toluene and MeOH (1 mL/0.5 mL). Compound 2a: Daicel
Chiralcel OJ-RH, HClO4 aq (pH 2)/MeCN = 70:30 (v/v), flow rate
0.3 mL/min, rt, detected at 254 nm. Compound 2b: Daicel Chiralcel
OD-RH, HClO4 aq (pH 2)/MeCN = 70:30 (v/v), flow rate 0.5 mL/min,
rt, detected at 254 nm. Compound 2c: Daicel Chiralcel OJ-RH, HClO4
aq (pH 2)/MeCN = 70:30 (v/v), flow rate 0.5 mL/min, rt, detected at
254 nm. Compound 2d methyl ester: Daicel Chiralcel AS-H, hex-
ane/i-PrOH = 90:10 (v/v), flow rate 0.5 mL/min, rt, detected at
254 nm. Compound 2e methyl ester: Daicel Chiralcel OD-H, hex-
ane/i-PrOH = 95:5 (v/v), flow rate 0.5 mL/min, rt, detected at
254 nm. Compound 2f methyl ester: Daicel Chiralcel OD, hexane/
i-PrOH = 95:5 (v/v), flow rate 0.5 mL/min, rt, detected at 254 nm.
The less-soluble (R)-1Á(S)-2f salt: CCDC 748068. Crystal data:
C19H25O4P, M = 348.37, monoclinic, space group P21, a = 10.520(5) Å,
b = 6.306(3) Å, c = 14.908(7) Å, V = 944.795 Å3, Z = 2, Dc = 1.225
Mg mÀ3, R = 0.0431.
Acknowledgments
We sincerely thank Dr. Yasuhiro Ishida for his valuable and
helpful discussion.
The present work was supported by the Grant-in-Aid for Scien-
tific Research from the Ministry of Education, Science, Sports and
Culture, Japan (No. 19350064). N.R. acknowledges the Japan Soci-
ety for the Promotion of Science (JSPS) for Postdoctoral Fellowship
for Foreign Researchers.
4.3. X-ray crystallographic analyses
References
X-ray crystallographic data were corrected on a Rigaku/MSC
1. (a) Jacques, J.; Collet, A.; Wilen, S. H. Enantiomers, Racemates and Resolutions;
Krieger Publishing: FL, 1994; (b) Collet, A. In Comprehensive Supramolecular
Chemistry; Reinhoudt, D. N., Ed.; Pergamon: Oxford, 1996; pp 113–149.
2. (a) Kinbara, K.; Saigo, K.. In Topics in Stereochemistry; Denmark, S. C., Ed.; Wiley &
Sons: New York, 2003; Vol. 23, pp 207–265; (b) Kinbara, K.; Katsumata, Y.;
Saigo, K. Chirality 2003, 15, 564–570; (c) Kobayashi, Y.; Kurasawa, T.; Kinbara, K.;
Saigo, K. J. Org. Chem. 2004, 69, 7436–7441; (d) Kobayashi, Y.; Kinbara, K.; Sato,
M.; Saigo, K. Chirality 2005, 17, 108–112; (e) Kobayashi, Y.; Saigo, K. J. Am. Chem.
Soc. 2005, 127, 15054–15060; (f) Shimada, T.; Kobayashi, Y.; Saigo, K.
Tetrahedron: Asymmetry 2005, 16, 3807–3813.
3. (a) Kobayashi, Y.; Morisawa, F.; Saigo, K. Org. Lett. 2004, 6, 4227–4230; (b)
Kobayashi, Y.; Morisawa, F.; Saigo, K. J. Org. Chem. 2006, 71, 606–615; (c)
Kobayashi, Y.; Maeda, J.; Morisawa, F.; Saigo, K. Tetrahedron: Asymmetry 2006,
17, 967–974; (d) Kobayashi, Y.; Maeda, J.; Saigo, K. Tetrahedron: Asymmetry
2006, 17, 1617–1621; (e) Kobayashi, Y.; Handa, H.; Maeda, J.; Saigo, K. Chirality
2008, 3, 577–584; (f) Ribeiro, N.; Kobayashi, Y.; Maeda, J.; Saigo, K. Chirality
Mercury diffractometer with graphite monochromated Mo K
radiation. The distance for the CH/ interaction corresponds to
the shortest distance from the carbon atom to the aromatic plane,
while the distance for the interaction corresponds to the short-
a
p
p/p
est distance between the two aromatic planes.
The less-soluble (R)-1Á(S)-2a salt: CCDC 748064. Crystal data:
C19H25O3P, M = 332.37, monoclinic, space group P21, a = 10.60(2)
Å, b = 6.271(13) Å, c = 13.93(3) Å, V = 919.063 Å3, Z = 2, Dc = 1.201
Mg mÀ3, R = 0.1097.
The less-soluble (R)-1Á(R)-2d salt: CCDC 748065. Crystal data:
C18H23O4P, M = 334.35, orthorhombic, space group P212121,
a = 6.106(4) Å, b = 21.855(13) Å, c = 26.964(15) Å, V = 3598.25 Å3,
Z = 8, Dc = 1.234 Mg mÀ3, R = 0.0812.
The more-soluble (R)-1Á(S)-2d salt: CCDC 748066. Crystal data:
C18H23O4P, M = 334.35, triclinic, space group P1, a = 6.196(4) Å,
b = 10.477(7) Å, c = 13.401 Å, V = 862.979 Å3, Z = 2, Dc = 1.287
Mg mÀ3, R = 0.0591.
The less-soluble (R)-1Á(S)-2e salt: CCDC 748067. Crystal data:
C18H22ClO4P, M = 368.79, monoclinic, space group P21,
a = 11.235(11) Å, b = 6.133(5) Å, c = 13.576(12) Å, V = 927.116 Å3,
Z = 2, Dc = 1.321 Mg mÀ3, R = 0.0448.
4. Drabowicz, J.; Lyzwa, P.; Omelanczuk, J.; Pietrusiewicz, M.; Mikolajczyk, M.
Tetrahedron: Asymmetry 1999, 10, 2757–2763.
5. The X-ray crystallography was carried out for single crystals obtained from the
enantiopure phosphine oxide (R)-1 and the enantiopure carboxylic acids (S)-2a,
(R)-2d, (S)-2d, (S)-2e and (S)-2f, respectively.
6. Desiraju, G. R. Acc. Chem. Res. 1996, 29, 441–444.
C
H
θ
d
D
O
C