Catalysts for Asymmetric Aldol Reactions
[2]
a) F. Silva, M. Sawicki, V. Gouverneur, Org. Lett. 2006, 8,
5417–5419; b) C. Zheng, Y. Wu, X. Wang, G. Zhao, Adv. Synth.
Catal. 2008, 350, 2690–2694; c) H. Zhang, S. Zhang, L. Liu,
G. Luo, W. Duan, W. Wang, J. Org. Chem. 2010, 75, 368–374;
d) N. Hara, R. Tamura, Y. Funahashi, S. Nakamura, Org. Lett.
2011, 13, 1662–1665.
a) B. List, R. A. Lerner, C. F. Barbas III, J. Am. Chem. Soc.
2000, 122, 2395–2396; b) B. List, P. Pojarliev, C. Castello, Org.
Lett. 2001, 3, 573–575; c) A. B. Northrup, D. W. C. MacMillan,
J. Am. Chem. Soc. 2002, 124, 6798–6799.
a) G. Guillena, C. Nájera, D. J. Ramón, Tetrahedron: Asym-
metry 2007, 18, 2249–2293; b) M. Gruttadauria, F. Giacalone,
R. Noto, Chem. Soc. Rev. 2008, 37, 1666–1688; c) H. Yang,
R. G. Carter, Synlett 2010, 2827–2838.
a) S. Bahmanyar, K. N. Houk, J. Am. Chem. Soc. 2001, 123,
11273–11283; b) F. R. Clemente, K. N. Houk, Angew. Chem.
2004, 116, 5890; Angew. Chem. Int. Ed. 2004, 43, 5766–5768.
a) M. B. Schmid, K. Zeitler, R. M. Gschwind, Angew. Chem.
2010, 122, 5117; Angew. Chem. Int. Ed. 2010, 49, 4997–5003;
b) B. List, L. Hoang, H. J. Martin, Proc. Natl. Acad. Sci. USA
2004, 101, 5839–5842; c) D. A. Bock, C. W. Lehmann, B. List,
Proc. Natl. Acad. Sci. USA 2010, 107, 20636–20641.
a) Z. Tang, F. Jiang, X. Cui, L.-Z. Gong, A.-Q. Mi, Y.-Z. Jiang,
Y.-D. Wu, Proc. Natl. Acad. Sci. USA 2004, 101, 5755–5760;
b) Z. Tang, Z.-H. Yang, X.-C. Chen, L.-F. Cun, A.-Q. Mi, Y.-
Z. Jiang, L.-Z. Gong, J. Am. Chem. Soc. 2005, 127, 9285–9289;
c) Y.-Q. Fu, Z.-C. Li, L.-N. Ding, J.-C. Tao, S.-H. Zhang, M.-
S. Tang, Tetrahedron: Asymmetry 2006, 17, 3351–3357; d) S.
Guizzetti, M. Benaglia, L. Pignataro, A. Puglisi, Tetrahedron:
Asymmetry 2006, 17, 2754–2760; e) S. Fotaras, C. Kokotos, E.
Tsandi, G. Kokotos, Eur. J. Org. Chem. 2011, 1310–1317.
a) J.-R. Chen, H.-H. Lu, X.-Y. Li, L. Cheng, J. Wan, W.-J.
Xiao, Org. Lett. 2005, 7, 4543–4545; b) Y. Okuyama, H. Nak-
ano, Y. Watanabe, M. Makabe, M. Takeshita, K. Uwai, C. Ka-
buto, E. Kwon, Tetrahedron Lett. 2009, 50, 193–197; c) R. L.
Sutar, N. N. Joshi, Tetrahedron: Asymmetry 2013, 24, 43–49.
a) C. Wang, Y. Jiang, X. Zhang, Y. Huang, B. Li, G. Zhang,
Tetrahedron Lett. 2007, 48, 4281–4285; b) S. S. Chimni, S.
Singh, D. Mahajan, Tetrahedron: Asymmetry 2008, 19, 2276–
2284; c) S. Zhang, X. Fu, S. Fu, Tetrahedron Lett. 2009, 50,
1173–1176; d) C. Shen, F. Shen, G. Zhou, H. Xia, X. Chen, X.
Liu, P. Zhang, Catal. Commun. 2012, 26, 6–10.
a) V. Maya, M. Raj, V. K. Singh, Org. Lett. 2007, 9, 2593–2595;
b) Y.-N. Jia, F.-C. Wu, X. Ma, G.-J. Zhu, C.-S. Da, Tetrahedron
Lett. 2009, 50, 3059–3062; c) S. Paladhi, J. Das, P. K. Mishra,
J. Dash, Adv. Synth. Catal. 2013, 355, 274–280.
a) S. Narayan, J. Muldoon, M. G. Finn, V. V. Fokin, H. C.
Kolb, K. B. Sharpless, Angew. Chem. 2005, 117, 3339; Angew.
Chem. Int. Ed. 2005, 44, 3275–3279; b) J. K. Beattie, S. S. P.
McErlean, C. B. W. Phippen, Chem. Eur. J. 2010, 16, 8972–
8974; c) N. Mase, C. F. Barbas III, Org. Biomol. Chem. 2010,
8, 4043–4050.
3.05 (dt, J = 6.8, 6.8, and 10.4 Hz, 1 H, 5-Hb), 3.79 (dd, J = 5.2
and 8.8 Hz, 1 H, 2-H), 4.11 (m, 1 H, CpH), 4.14 (m, 2 H, CpH),
4.18 (m, 1 H, CpH), 4.21 (s, 5 H, CpЈH), 4.76 (dq, J = 6.8 and
7.2 Hz, 1 H, CHN), 7.96 (d, J = 7.2 Hz, 1 H, CONH) ppm. 13C
NMR (100 MHz, CDCl3): δ = 20.8 (CH3), 26.2 (C-4), 30.9 (C-3),
42.6 (CH2N), 47.3 (C-5), 60.6 (C-2), 65.9 (CpH), 67.1 (CpH), 67.7
(2 CpH), 68.4 (CpЈH), 91.8 (Cp), 173.8 (CO) ppm. [α]D = –55.4
(c = 1.1, CHCl3). CD: λ (Δε) = 457 (+0.094). HRMS: calcd. for
C17H23FeN2O [M + H]+ 327.1154; found 327.1152.
[3]
[4]
General Procedure for Aldol Reaction: The catalyst (0.0125 mmol)
of choice and PhCOOH (0.0125 mmol) were taken from stock solu-
tions in CH2Cl2 and combined in a screw-capped vial (12 mL). Af-
ter removal of the solvent under a gentle stream of nitrogen, cyclo-
hexanone (0.5 mmol), the aldehyde (0.25 mmol), and brine
(0.5 mL) were sequentially added, and the resultant suspension was
maintained at –10 °C under vigorous stirring for the required time.
The reaction mixture was then diluted with AcOEt, and the aque-
ous phase was discarded. The organic phase was dried with Na2SO4
and filtered, and the solution was concentrated under vacuum. The
residue was applied to a short plug of silica gel (AcOEt) to recover
all the reaction components except the catalyst. The solvent was
evaporated to give a residue that was analyzed by 1H NMR to
determine the anti/syn ratio of the aldol product. The residue was
then applied to a chromatographic column (silica gel, n-hexane/
AcOEt, 8:2) to afford the pure anti-aldol product as a white solid,
and the enantiomeric composition was determined by chiral
HPLC. The aldol products from the reactions with cyclopentanone
could not be separated and were analyzed as syn/anti dia-
stereomeric mixtures.
[5]
[6]
[7]
[8]
[9]
Preparative Synthesis of (S)-2-[(R)-Hydroxy(2-nitrophenyl)methyl]-
cyclohexan-1-one: In
a vial (30 mL), catalyst 9b (40.8 mg,
0.125 mmol) and benzoic acid (15.3 mg, 0.125 mmol) were sus-
pended in brine (5 mL). To this suspension were added 2-nitrobenz-
aldehyde (377.5 mg, 2.5 mmol) and cyclohexa-none (520 μL,
492.4 mg, 5.0 mmol), and the mixture was vigorously stirred at
room temperature for 4 h. The mixture was then diluted with Ac-
OEt (5 mL), and the aqueous layer was discarded. The organic
phase was dried with Na2SO4 and concentrated to give a residue
that was purified by column chromatography (silica gel, n-hexane/
AcOEt, 8:2) to afford the pure title compound (480.5 mg,
1.93 mmol, 77% yield, 90%ee) and the syn diastereomer (60.3 mg,
0.24 mmol, 9.6% yield). Catalyst 9b was recovered quantitatively
after elution with AcOEt/triethylamine (1:1). The enantiopure anti-
[10]
[11]
aldol product {312.6 mg, 1.25 mmol, 65% yield, Ͼ99%ee, [α]2D5
=
+14.6 (c = 0.53, CHCl3)} was obtained in the mother liquor during
crystallization (n-hexane/CH2Cl2, 5:1), from which crystals
(67%ee) were isolated.
[12]
a) N. Mase, Y. Nakai, N. Ohara, H. Yoda, K. Takabe, F.
Tanaka, C. F. Barbas III, J. Am. Chem. Soc. 2006, 128, 734–
735; b) Y. Hayashi, S. Aratake, T. Okano, J. Takahashi, T. Su-
miya, M. Shoji, Angew. Chem. 2006, 118, 5653; Angew. Chem.
Int. Ed. 2006, 45, 5527–5529; c) J. Huang, X. Zhang, D. Arm-
strong, Angew. Chem. 2007, 119, 9231; Angew. Chem. Int. Ed.
2007, 46, 9073–9077; d) F. Giacalone, M. Gruttadauria, P. Ag-
rigento, P. Lo Meo, R. Noto, Eur. J. Org. Chem. 2010, 5696–
5704.
M. H. Abraham, N. Benjelloun-Dakhama, J. M. R. Gola,
W. E. Acree, W. S. Cain, J. E. Cometto-Muniz, New J. Chem.
2000, 24, 825–829.
P. Stepnicka (Ed.), Ferrocenes: Ligands, Materials and Biomole-
cules, Wiley-VCH, Weinheim, Germany, 2008.
Supporting Information (see footnote on the first page of this arti-
cle): Detailed experimental procedures, 1H and 13CNMR spectra
of ferrocenylamides 3, 4, 8, 9a, and 9b, and 1H and 13C NMR
spectra and chiral HPLC data and chromatograms of aldol prod-
ucts reported in Table 4.
Acknowledgments
[13]
Thanks are due to Dr. Giuseppe Di Natale for the HRMS spectra
acquisition at CNR-Myrmex Laboratory.
[14]
[15]
[16]
M. F. R. Fouda, M. M. Abd-Elzaher, R. A. Abdesamaia, A. A.
Labib, Appl. Organomet. Chem. 2007, 21, 613–625.
R. G. Arrayás, J. Adrio, J. C. Carretero, Angew. Chem. 2006,
118, 7836; Angew. Chem. Int. Ed. 2006, 45, 7674–7715.
[1] For recent reviews, for example, see: a) B. M. Trost, C. S. Brin-
dle, Chem. Soc. Rev. 2010, 39, 1600–1632; b) V. Bisai, A. Bisai,
V. K. Singh, Tetrahedron 2012, 68, 4541–4580; c) J. Mlynarski,
B. Gut, Chem. Soc. Rev. 2012, 41, 587–596.
Eur. J. Org. Chem. 2014, 624–630
© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
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