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Synlett 2004(15): 2785-2787  
DOI: 10.1055/s-2004-835642
LETTER
© Georg Thieme Verlag Stuttgart · New York

Ytterbium(III) Triflate-Catalyzed Conversion of Carbonyl Compounds into 1,3-Oxathiolanes in Ionic Liquids

Anil Kumar, Nidhi Jain, Sandeep Rana, Shive M. S. Chauhan*
Department of Chemistry, University of Delhi, Delhi 110 007, India
e-Mail: smschauhan@chemistry.du.ac.in;
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Publikationsverlauf

Received 25 May 2004
Publikationsdatum:
08. November 2004 (online)

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Abstract

The reaction of carbonyl compounds with 2-mercapto­ethanol to prepare 1,3-oxathiolanes has been successfully carried out in ionic liquids using ytterbium(III) triflate as a catalyst. Yields of the products are high and the catalyst can be easily recovered and reused in this reaction.

Key words

carbonyl compounds - 1,3-oxathiolanes - ionic liquid - ytterbium(III) triflate

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Representative Experimental Procedure for the Reac-tion of 4-Nitrobenzaldehyde with 2-Mercaptoethanol:
To a mixture of 4-nitrobenzaldehyde (151 mg, 1 mmol) and Yb(OTf)3 (6.2 mg, 0.01 mmol) in [bmim][PF6] (3 mL) was added 2-mercaptoethanol (117 mg, 1.5 mmol) and the contents were stirred at r.t. for about 1 h. The product was extracted with a mixture of hexane-EtOAc (1:1 v/v, 3 × 10 mL) and this organic extract was washed with 10% NaHCO3 solution and then with H2O. The organic layer was dried over anhyd Na2SO4 and concentrated under reduced pressure to yield 2-(4-nitrobenzyl)-1,3-oxathiolane in 98% yield. The products were characterized by 1H NMR spectroscopic data and CHN analysis.

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Data of Selected Oxathiolanes:
2-(4-Methylphenyl)-1,3-oxathiolane ( 2): Anal. Calcd for C10H12OS: C, 66.66; H, 6.68; S, 17.77. Found: C, 66.48; H, 6.72; S, 17.54. 1H NMR (300 MHz, CDCl3, TMS): δ = 7.17 (2 H, d, J = 8 Hz), 6.99 (2 H, d, J = 8 Hz), 5.17 (1 H, s), 4.26-4.28 (1 H, m), 3.84-3.88 (1 H, m), 3.22-3.25 (1 H, m), 3.02-3.06 (1 H, m), 2.13 (3 H, s).
2-(3,4-Methylenedeoxyphenyl)-1,3-oxathiolane ( 9): Anal. Calcd for C10H10O3S: C, 57.14; H, 4.76; S, 15.23. Found: C, 57.45; H, 4.57; S, 15.37. 1H NMR (300 MHz, CDCl3): δ = 6.64 (1 H, d, J = 9 Hz), 6.59 (1 H, s,), 5.90 (2 H, s), 5.17 (1 H, s), 4.30-4.32 (1 H, m), 3.90-3.94 (1 H, m), 3.24-3.29 (1 H, m), 3.12-3.16 (1 H, m). 2-(2-Furyl)-1,3-oxathiolane ( 10): Anal. Calcd for C7H8O2S: C, 53.80; H, 5.12; S, 20.50. Found: C, 53.61; H, 5.25; S, 20.68. 1H NMR (300 MHz, CDCl3): δ = 7.30, (1 H, d, J = 8 Hz), 6.25 (1 H, m), 6.19 (1 H, d, J = 8 Hz), 5.40 (1 H, s), 4.20-4.22 (1 H, m), 3.70-3.74 (1 H, m), 3.12-3.18 (1 H, m), 2.90-2.96 (1 H, m).
2-(3-Pyridyl)-1,3-oxathiolane ( 11): Anal. Calcd for C8H9OSN: C, 57.48; H, 5.38; N, 8.30; S, 19.16. Found: C, 57.32; H, 5.18; N, 8.45; S, 19.05. 1H NMR (300 MHz, CDCl3): δ = 8.70 (1 H, s, J = 8, 7 Hz), 8.55 (1 H, dd, J = 8, 3 Hz), 7.90 (1 H, dd, J = 8, 3 Hz), 7.42 (1 H, dd, J = 8, 7 Hz), 5.17 (1 H, s), 4.40-4.42 (1 H, m), 3.92-3.96 (1 H, m), 3.30-3.36 (1 H, m), 3.22-3.26 (1 H, m).
2-(4-Methylamino-3-nitrophenyl)-1,3-oxathiolane ( 12): Anal. Calcd for C10H12O3N2S: C, 50.12; H, 5.00; N, 11.66; S, 13.33. Found: C, 50.38; H, 5.16; N, 11.48; S, 13.20. 1H NMR (300 MHz, CDCl3): δ = 7.98 (1 H, d, J = 3 Hz), 7.57 (1 H, dd, J = 9, 3 Hz), 7.52 (1 H, d, J = 9 Hz), 6.05 (1 H, s), 4.52 (1 H, m), 4.00 (1 H, m), 3.24 (2 H, m).
2-Methyl-2-phenyl-1,3-oxathiolane ( 13): Anal. Calcd for C10H12OS: C, 66.66; H, 6.66; S, 17.77. Found: C, 66.45; H, 6.43; S, 17.90. 1H NMR (300 MHz, CDCl3): δ = 7.08-7.18 (3 H, m), 7.21 (2 H, m), 4.10-4.14 (1 H, m), 3.82 (1 H, m), 3.10 (2 H, m), 1.83 (3 H, s).
Cyclohexyl-1,3-oxathiolane ( 14): Anal. Calcd for C8H14OS: C, 60.75; H, 8.86; S, 20.25. Found: C, 60.58; H, 8.42; S, 20.45. 1H NMR (300 MHz, CDCl3): δ = 4.42 (1 H, m), 4.17 (2 H, t, J = 11.4 Hz), 3.80-3.86 (1 H, m), 3.24 (1 H, m), 3.10 (1 H, m), 3.03 (2 H, t, J = 11.4 Hz), 1.82 (6 H, m), 1.50 (4 H, m).
2-Tetralonyl-1,3-oxathiolane ( 15): Anal. Calcd for C12H14OS: C, 69.90; H, 6.79; S, 15.53. Found: C, 69.78; H, 6.64; S, 15.42. 1H NMR (300 MHz, CDCl3): δ = 6.93-7.24 (4 H, m), 4.53-4.55 (1 H, m), 3.70-3.74 (1 H, m,), 3.29-3.34 (1 H, m), 3.18-3.20 (1 H, m), 2.85 (2 H, t, J = 11 Hz), 2.06 (2 H, t, J = 11 Hz), 1.60 (2 H, m).
2-Phenyl-2-phenyl-1,3-oxathiolane ( 17): Anal. Calcd for C15H14OS: C, 74.38; H, 5.78; S, 13.22. Found: C, 74.1; H, 5.64; S, 13.12. 1H NMR (300 MHz, CDCl3): δ = 7.19-7.28 (6 H, m), 7.30-7.38 (4 H, m), 4.42-4.44 (1 H, m), 3.80-3.84 (1 H, m), 3.34-3.39 (1 H, m), 3.16 (1 H, m).