The Journal of Organic Chemistry
Note
evaporated, giving a residue rich in (S)-1c. Similar treatment of the
residue gave (S)-1c in 58% yield (5.75 g, 8.78 mmol, 72% ee) and (R)-
2b in 49% yield (3.24 g, 11.3 mmol). The high enantiomeric (S)-1c
was obtained as follows: (S)-1c with 72% ee (2.80 g, 4.28 mmol) was
dissolved in toluene (30 mL) at reflux, and the obtained homogeneous
solution was allowed to cool to room temperature. After overnight, the
precipitate of rac-1a was filtered off (610 mg, 0.93 mmol, 22% yield).
The toluene solution left after separation of rac-1a was evaporated,
giving the solid of (S)-1c with 94% ee in 74% yield (2.07 g, 3.16 mmol).
Further enhancement of enantiopurity could not been achieved by
recrystallization using (S)-1c with 94% ee. Enantioresolution of 1a
(2.00 g, 3.05 mmol) was also achieved by using 2c (1.30 g, 4.54 mmol)
instead of 2b, giving 1c with 99% ee in 43% yield (860 mg, 1.31 mmol)
and 1b with 67% ee in 56% yield (1.12 g, 1.71 mmol). Enantiomeric
excess was determined by HPLC analysis with a Chiralcel AD-H
column (hexane/2-propanol = 90:10), 1.0 mL/min, 280 nm. Spectral
data for inclusion complex 3: white solid; mp 133.5−137.2 °C (from
hexane−CH2Cl2); soluble in CH2Cl2, CHCl3, EtOH, MeOH, and
toluene; IR (KBr) 3477, 3406, 3053, 1507, 1339, 1286, 1185, 972 cm−1;
1H NMR (500 MHz, CDCl3) δ 5.26 (CH2Cl2 as crystal solvent), 6.14
(br, 4H), 6.77 (d, 4H, J = 3.7 Hz), 7.08−7.11 (m, 8H), 7.18−7.37
(m, 28H), 7.59−7.67 (m, 8H), 7.81−7.84 (m, 8H); 13C NMR (125 MHz,
CDCl3) δ 53.4 (CH2Cl2 as crystal solvent), 112.1, 118.1, 123.4, 124.6,
125.9, 126.8, 126.9, 127.3, 127.8, 127.9, 127.9, 128.0, 128.1, 129.1,
130.5, 131.1, 131.3, 131.9, 132.0, 132.4, 132.5, 133.7, 134.0, 152.9; 31P
NMR (200 MHz, CDCl3) δ 32.4. Anal. Calcd for C86H64Cl4O6P2: C,
73.93; H, 4.62. Found: C, 74.40; H, 4.62.
(c) Bayaedon, J.; Cavazzini, M.; Maikkard, D.; Pozzi, G.; Quici, S.;
Sinou, D. Tetrahedron: Asymmetry 2003, 14, 2215−2224.
(3) Takaya, H.; Mashima, K.; Koyano, K.; Yagi, M.; Kumobayashi,
H.; Taketomi, T.; Akutagawa, S.; Noyori, R. J. Org. Chem. 1986, 51,
629−635.
(4) For a cocrystal of 1b with hydroquinone, see: Yenikaya, C.;
̈
Og
retir, C.; Berber, H. THEOCHEM 2005, 713, 171−177.
(5) Chiral 1 was also obtained by oxidation of chiral BINAP (2,2′-
bis(diphenylphosphino)-1,1′-binaphthyl), which was prepared from
optically active BINOL (2) as a starting material. For oxidation of
BINAP, see ref 1d. For preparation of chiral BINAP, see: (a) Cai, D.;
Payack, J. F.; Bender, D. R.; Hughes, D. L.; Verhoeven, T. R.; Reider,
P. J. J. Org. Chem. 1994, 59, 7180−7181. (b) Sayo, N.; Zhang, X.;
Ohmoto, T.; Yoshida, A.; Yokozawa, T. Eur. Pat., 0,771,812, 1997.
(c) Zhang, X.; Sayo, N.; Eur. Pat., 0,839,819, 1998.
(6) (a) Hatano, B.; Hirano, S.; Yanagihara, T.; Toyota, S.; Toda, F.
Synthesis 2001, 1181−1184. (b) Hatano, B.; Aikawa, A.; Tagaya, H.;
Takahashi, H. Chem. Lett. 2004, 33, 1276−1277. (c) Hatano, B.;
Aikawa, A.; Katagiri, H.; Tagaya, H.; Takahashi, H. Chem. Lett. 2007,
36, 1272−1273.
(7) The enantioresolution of amine N-oxide using an inclusion
complex with chiral 2 was reported; see: Nakajima, M.; Sasaki., Y.;
Shiro, M.; Hashimoto, S. Tetrahedron: Asymmetry 1997, 8, 341−344.
(8) For preparation of BINAPO (1a), see ref 1d.
Crystal data for inclusion complex 3: C44H32O2P2·
2(C20H14O2)·2(CH2Cl2), M = 1397.11, tetragonal, a = 11.2117(2) Å, ?
>b = 11.2117(2) Å, c = 54.8735(10) Å, α = 90.00°, β = 90.00°, γ =
90.00°, V = 6897.7(2) Å3, T = 93 K, space group P41, Z = 4, 130489
reflections measured, 12628 independent reflections (Rint = 0.0663). The
final R1 values were 0.0399 (I > 2σ(I)). The final wR(F2) values were
0.1032 (I > 2σ(I)). The final R1 values were 0.0400 (all data). The final
wR(F2) values were 0.1033 (all data).
ASSOCIATED CONTENT
* Supporting Information
■
S
NMR spectra of 1a and 3, CIF of 3, and HPLC data for
enantioresolution of 1a. This material is available free of charge
AUTHOR INFORMATION
Corresponding Author
*Tel: +81-238-26-3117. Fax:+81-238-26-3413. E-mail:
■
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
This work was supported by a Grant-in-Aid for Scientific
Research (C) from the JSPS KAKENHI (No. 23550187).
■
REFERENCES
■
(1) For organocatalyst, see: (a) Ogawa, C.; Sugiura, M.; Kobayashi, S.
Angew. Chem., Int. Ed. 2004, 43, 6491−6493. (b) Nakajima, M.;
Kotani, S.; Ishizuka, T.; Hashimoto, S. Tetrahedron Lett. 2005, 46,
157−159. (c) Tokuoka, E.; Kotani, S.; Matsunaga, H.; Ishizuka, T.;
Hashimoto, S.; Nakajima, M. Tetrahedron: Asymmetry 2005, 16, 2391−
2392. (d) Kotani, S.; Hashimoto, S.; Nakajima, M. Tetrahedron 2007,
63, 3122−3132. (e) Shimoda, Y.; Tando, T.; Kotani, S.; Sugiura, M.;
Nakajima, M. Tetrahedron: Asymmetry 2009, 20, 1369−1370.
(f) Kotani, S.; Aoki, S.; Sugiura, M.; Nakajima, M. Tetrahedron Lett.
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(2) For chiral ligand, see: (a) Mikami, K.; Yamaoka, M. Tetrahedron
Lett. 1998, 39, 4501−4504. (b) Fan, Q.-H.; Liu, G.-H.; Deng, G.-J.;
Chen, X.-M.; Chan, A. S. C. Tetrahedron Lett. 2001, 42, 9047−9050.
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