PAPER
Resolution of Betti Base
901
1-(α-Aminobenzyl)-2-naphthol Trifluoroacetate (4)
To a soln of oxazine 2 (20 g, 59.3 mmol) in CH2Cl2 (200 mL) and
H2O (2.1 mL) was added TFA (8.8 mL, 118.6 mmol) dropwise at
r.t. The mixture was stirred at 50 °C for 5 h and then cooled to 10
°C and filtered to obtain a solid that was washed with cold CH2Cl2
and dried in vacuo to give racemic 4; yield: 20.7 g (57.0 mmol,
96%); mp 160–162 °C.
extracted with Et2O (3 × 20 mL). The Et2O phase was washed with
sat. aq NaCl, dried (Na2SO4), and concentrated in vacuo to give (S)-
3 as a white solid; yield: 0.65 g (2.6 mmol, 99%); 99% ee [S, ma-
jor];8 mp 132–133 °C (Lit.6 133–134 °C); [α]D25 +55.8 (c 4.0, ben-
25
zene) [Lit.6 [α]D +56.6 (c 4.0, benzene)]; Rf = 0.3 (hexanes–
EtOAc, 2:1).
1H NMR (400 MHz, DMSO-d6): δ = 7.87 (d, J = 8.6 Hz, 1 H), 7.75
(d, J = 8.1 Hz, 1 H), 7.71 (d, J = 8.8 Hz, 1 H), 7.49 (d, J = 7.7 Hz, 2
H), 7.37–7.19 (m, 7 H), 7.04 (d, J = 8.8 Hz, 1 H), 6.08 (s, 1 H).
13C NMR (100 MHz, DMSO-d6): δ = 157.8, 144.1, 132.3, 129.3,
128.9, 128.2, 127.8, 127.7, 126.7, 122.4, 122.0, 120.8, 117.4, 55.0.
IR (KBr): 3290, 3070, 2920, 1675, 1210, 1130 cm–1.
1H NMR (400 MHz, DMSO-d6): δ = 11.02 (br s, 1 H), 8.83 (br s, 3
H), 8.07 (d, J = 8.6 Hz, 1 H), 7.90–7.87 (m, 2 H), 7.53–7.49 (m, 3
H), 7.40–7.30 (m, 5 H), 6.32 (s, 1 H).
13C NMR (100 MHz, DMSO-d6): δ = 158.7 (q, J = 31.2 Hz), 154.1,
138.0, 132.3, 131.2, 129.3, 129.0, 128.6, 128.5, 127.8, 127.6, 123.5,
122.2, 119.1, 117.7 (q, J = 299.8 Hz), 114.4, 51.6.
(R)-1-(α-Aminobenzyl)-2-naphthol [(R)-3]
To the mother liquor from the resolution of racemic 4 was added
H2O (100 mL) dropwise and the mixture was stirred for 2 h. The in-
soluble substance was separated by filtration, washed with CH2Cl2
and dried in vacuo to give crude (R)-4 (0.98 g, 98%). Without puri-
fication, the crude (R)-4 was added to 2 M Na2CO3 soln (10 mL).
Then the mixture was stirred for 30 min and extracted with Et2O (3
× 10 mL). The Et2O phase was washed with sat. aq NaCl, dried
(Na2SO4), and concentrated in vacuo to give (R)-3 as a white solid;
yield: 0.64 g (2.5 mmol, 93% yield from 4); 90% ee [R, major].8
MS (ESI): m/z (%) = 250 (52) [M – CF3COO]+, 233 (100).
Anal. Calcd for C19H16F3NO3: C, 62.81; H, 4.44; N, 3.86. Found: C,
62.71; H, 4.45; N, 3.85.
(R)-1,1′-Binaphthalene-2,2′-diyl Sodium Phosphate (5)
A 250-mL Schlenk flask was evacuated, refilled with argon, and
charged with a soln of (R)-1,1′-bi-2-naphthol (10 g, 34.9 mmol) in
pyridine (50 mL). The soln was cooled to 0 °C in an ice bath and
POCl3 (6.4 mL, 70 mmol) was added dropwise. When the addition
was complete, the mixture was warmed to 60 °C and stirred for 5 h,
and then the solvent was completely removed in vacuo. The residue
was dissolved in sat. Na2CO3 soln (100 mL) and then refluxed for 2
h. After cooling the reaction to r.t., the mixture was filtered. The res-
idue was washed with H2O and dried in vacuo to give 5 as a pow-
Recycled (R)-1,1′-Binaphthalene-2,2′-diyl Sodium Phosphate
(5)
The remaining aqueous phase after extracting (S)-3 was filtered.
The residue was washed with H2O and Et2O and then dried in vacuo
to give 5 (0.9 g, 90%) as a colorless solid. The recycled (R)-1,1′-bi-
naphthalene-2,2′-diyl sodium phosphate (5) was reused for resolu-
tion of racemic 1-(α-aminobenzyl)-2-naphthol trifluoroacetate (4).
25
dered colorless solid; yield: 11.2 g (85%); mp >320 °C; [α]D
–254.3 (c 0.82, THF).
IR (KBr): 3630, 3360, 3055, 1250, 1100, 970, 860, 750 cm–1.
1H NMR (400 MHz, DMSO-d6): δ = 8.03 (t, J = 8.8 Hz, 4 H), 7.45–
7.41 (m, 4 H), 7.30 (t, J = 7.4 Hz, 2 H), 7.23 (d, J = 8.5 Hz, 2 H).
Acknowledgment
We thank the Natural Science Foundation of Fujian Province, China
(Grant No. 2010J01055).
13C NMR (100 MHz, DMSO-d6): δ = 150.7, 150.6, 132.5, 130.8,
130.1, 128.8, 126.5, 124.8, 123.1, 122.2.
Supporting Information for this article is available online at
31P NMR (162 MHz, DMSO-d6): δ = 5.3.
MS (ESI): m/z (%) = 347 (100) [M – Na]–.
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Anal. Calcd for C20H12NaO4P·0.5 H2O: C, 63.33; H, 3.45. Found: C,
63.22; H, 3.46.
References
(1) (a) Cardellicchio, C.; Capozzi, M. A. M.; Naso, F.
Tetrahedron: Asymmetry 2010, 21, 507. (b) Szatmári, I.;
Fülöp, F. Curr. Org. Synth. 2004, 1, 155.
(S)-1-(α-Aminobenzyl)-2-naphthol Diastereomeric Salt 6
To a soln of 4 (2.0 g, 5.5 mmol) in anhyd THF (5 mL) at 50 °C was
added a soln of 5 (1.0 g, 2.8 mmol) in anhyd THF (7 mL). The mix-
ture was stirred at 50 °C for 2 h and then stirred at r.t. for 3 h. The
sediments were separated by filtration [the mother liquor was re-
tained and used to obtain (R)-4] and washed with MeOH–Et2O (1:5,
10 mL), and dried in vacuo to give 6 as a colorless solid; yield 1.58
g (96%); mp 199–201 °C; [α]D20 –286.8 (c 1.0, MeOH).
(2) (a) Su, D. Y.; Wang, X. Y.; Shao, C. W.; Xu, J. M.; Zhu, R.;
Hu, Y. F. J. Org. Chem. 2011, 76, 188. (b) Metlushka, K. E.;
Sadkova, D. N.; Shaimardanova, L. N.; Kataeva, O. N.;
Alfonsov, V. A. Phosphorus, Sulfur Silicon Relat. Elem.
2011, 186, 712. (c) Liu, G. X.; Zhang, S. L.; Li, H.; Zhang,
T. Z.; Wang, W. Org. Lett. 2011, 13, 828. (d) Durmaz, M.;
Yilmaz, M.; Sirit, A. Org. Biomol. Chem. 2011, 9, 571.
(e) Durmaz, M.; Bozkurt, S.; Naziroglu, H. N.; Yilmaz, M.;
Sirit, A. Tetrahedron: Asymmetry 2011, 22, 791. (f) Yang,
Y. X.; Dai, X.; Zhou, H. L.; Dong, Y. F.; Wang, X. F. Wuji
Huaxue Xuebao 2010, 26, 1013. (g) Ma, F. N.; Ai, L.; Shen,
X. M.; Zhang, C. Org. Lett. 2007, 9, 125. (h) Kaiser, P. F.;
White, J. M.; Hutton, C. A. J. Am. Chem. Soc. 2008, 130,
16450. (i) Wang, X. Y.; Dong, Y. M.; Sun, J. W.; Xu, X. N.;
Li, R.; Hu, Y. F. J. Org. Chem. 2005, 70, 1897.
IR (KBr): 3055, 2920, 1500, 1220, 1080, 960 cm–1.
1H NMR (400 MHz, DMSO-d6): δ = 11.22 (br s, 1 H), 8.80 (br s, 3
H), 8.06–7.98 (m, 5 H), 7.82 (d, J = 8.0 Hz, 1 H), 7.71 (d, J = 8.9
Hz, 1 H), 7.49–7.26 (m, 16 H), 6.25 (s, 1 H).
13C NMR (100 MHz, DMSO-d6): δ = 154.3, 150.5, 138.0, 132.5,
132.3, 131.0, 130.8, 130.2, 129.2, 128.9, 128.5, 127.6, 126.5, 124.9,
123.4, 123.1, 122.2, 119.1, 114.2, 51.6.
31P NMR (162 MHz, DMSO-d6): δ = 4.6.
MS (ESI): m/z (%) = 598 (100) [M + H]+, 250 (52), 233 (60).
(3) Betti, M. Org. Synth. 1929, 9, 60.
(4) Cardellicchio, C.; Ciccarella, G.; Naso, F.; Schingaro, E.;
Scordari, F. Tetrahedron: Asymmetry 1998, 9, 3667.
(5) (a) Szatmári, I.; Fülöp, F. Synthesis 2009, 775. (b) Ghandi,
M.; Olyaei, A.; Raoufmoghaddam, S. Synth. Commun. 2008,
38, 4125.
Anal. Calcd for C37H28NO5P: C, 74.36; H, 4.72; N, 2.34. Found: C,
74.16; H, 4.73; N, 2.33.
(S)-1-(α-Aminobenzyl)-2-naphthol [(S)-3]
The salt 6 was suspended in H2O, followed by the addition of 2 M
Na2CO3 soln (30mL). Then the mixture was stirred for 30 min and
© Georg Thieme Verlag Stuttgart · New York
Synthesis 2013, 45, 899–902