LETTER
Water-Tolerant Chiral Indium Complex
817
(6) Reactions with aliphatic aldehydes or aliphatic amines
afforded the products in low yields.
References and Notes
(1) (a) Li, C.-J.; Chan, T.-H. Organic Reactions in Aqueous
Media; John Wiley & Sons: New York, 1997. (b) Organic
Synthesis in Water; Grieco, P. A., Ed.; Blacky Academic and
Professional: London, England, 1998.
(2) Loh, T.-P.; Chua, G.-L. Chem. Commun. 2006, 2739.
(3) (a) Teo, Y.-C.; Tan, K.-T.; Loh, T.-P. Chem. Commun. 2005,
1318. (b) Teo, Y.-C.; Goh, J.-D.; Loh, T.-P. Org. Lett. 2005,
7, 2743. (c) Teo, Y.-C.; Loh, T.-P. Org. Lett. 2005, 7, 2539.
(d) Lu, J.; Ji, S.-J.; Teo, Y.-C.; Loh, T.-P. Org. Lett. 2005, 7,
159. (e) Lu, J.; Hong, M.-L.; Ji, S.-J.; Loh, T.-P. Chem.
Commun. 2005, 1010. (f) Lu, J.; Ji, S.-J.; Teo, Y.-C.; Loh,
T.-P. Tetrahedron Lett. 2005, 46, 7435.
(7) Typical Reaction Procedure: Anhydrous benzaldehyde
(0.05 mL, 0.5 mmol) and indium complex 4 (20 mg, 0.025
mmol) were mixed and stirred at r.t. in H2O (5 mL) for 10
min before the addition of anhyd aniline (0.06 mL, 0.6
mmol). The resulting mixture was stirred at r.t. for 30 min.
1-Methoxy-1-trimethylsilyloxypropene (0.2 mL, 1 mmol)
was then added. The suspension was stirred at r.t. for 1 d and
then extracted with EtOAc (3 × 25 mL). The organic layers
were combined, washed with brine (5 mL), dried over anhyd
MgSO4, and concentrated under reduced pressure. The
product was obtained in 69% yield after silica gel column
chromatography as a yellowish wet solid; Rf 0.61 (hexane–
EtOAc, 4:1). 1H NMR (CDCl3): d = 7.23–7.31 (m, 5 H),
7.03–7.10 (m, 2 H), 6.50–6.65 (m, 3 H), 4.53 (s, 1 H), 3.67
(s, 3 H), 1.30 (s, 3 H), 1.20 (s, 3 H). 13C NMR (CDCl3): d =
176.97, 146.86, 139.17, 128.95, 128.21, 127.93, 127.38,
117.22, 113.34, 64.30, 52.01, 46.95, 24.48, 20.65. FTIR
(thin film): 1715.8 cm–1. HRMS: m/z calcd for C18H21NO2:
283.1572; found: 283.1568.
(4) Teo, Y.-C.; Goh, E.-L.; Loh, T.-P. Tetrahedron Lett. 2005,
46, 6209.
(5) Crystal Data: C21H39C4InO12S2, M = 804.26, colorless prism.
Crystal dimensions: 0.20 × 0.15 × 0.04 mm, monoclinic,
space group P2(1), a = 6.9145(2) Å, b = 15.3916(6) Å, c =
15.5826 (6) Å, V = 1657.02(10) Å3, Z = 2, Dc = 1.612 Mg/
m3. Reflections collected: 34477; independent reflections:
7580 (Rint = 0.0432), final R[I > 2s(I)] = 0.0428, R (all
data) = 0.0535, Rw = 0.1327. Crystallographic data for this
crystal has been deposited with the Cambridge
(8) (a) Loh, T.-P.; Liung, S. B. K. W.; Tan, K.-L.; Wei, L.-L.
Tetrahedron 2000, 56, 3227. (b) Loh, T.-P.; Wei, L.-L.
Tetrahedron Lett. 1998, 39, 323.
Crystallographic Data Center as supplementary publication
number CCDC 624125. Copies of the data can be obtained
free of charge on application to CCDC, 12 Union Road
Cambridge CB2, 1EZ, UK [fax: +44(1223)336033; e-mail:
deposit@ccdc.cam.ac.uk].
(9) The drop in reactivity by the fourth or fifth cycle may be
attributed to loss of catalyst due to organic extraction.
Synlett 2007, No. 5, 815–817 © Thieme Stuttgart · New York