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Synlett 2008(7): 987-990  
DOI: 10.1055/s-2008-1072508
LETTER
© Georg Thieme Verlag Stuttgart · New York

A New Application of Hypervalent Iodine (λ5) Reagents with Organosulfonic Acids for Direct α-Organosulfonyloxylation Carbonyl Compounds

Ulhas S. Mahajan, Krishnacharya G. Akamanchi*
Department of Pharmaceutical Sciences & Technology, Institute of Chemical Technology, Matunga, Mumbai 400 019, India
Fax: +91(22)24145614; e-Mail: kgap@rediffmail.com;
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Publication History

Received 22 November 2007
Publication Date:
17 March 2008 (online)

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Abstract

Hypervalent iodine (λ5) reagents in combination with p-toluenesulfonic acid when reacted with ketones under reflux temperature in acetonitrile gave α-tosyloxy ketones in moderate to excellent yields. The reaction was developed further for both ketones and dicarbonyl compounds using Dess-Martin periodinane reagent in combination with p-toluenesulfonic acid and methanesulfonic acid, to give mono-α-tosyloxy and mono-α-mesyloxy products in very high to excellent yields.

Key words

hypervalent iodine reagents - Dess-Martin periodinane - carbonyl compounds - organosulfonic acids - α-organosulfonyl­oxylation

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General Experimental Procedure for α-Organo-sulfonyloxylation
To a stirred suspension of Dess-Martin periodinane (3.5 g, 7.5 mmol) and organosulfonic acid (10 mmol) in MeCN (15 mL) was added the substrate (5 mmol) in one portion and the reaction mixture was refluxed until complete consumption of starting material (monitored by TLC). After completion of reaction MeCN was removed under reduced pressure. The residue obtained was diluted by adding CHCl3 (50 mL) and washed with sat. solutions of NaHCO3 (2 × 30 mL) and brine (50 mL). The organic layer was dried over anhyd Na2SO4 and concentrated under reduced pressure to give the crude α-organosulfonyloxylated product. Pure product was obtained after column chromatography (SiO2, mesh size 60-120, eluent, EtOAc-hexane, 15:85).

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Spectroscopic Data for Selected of α-Tosyloxylated and α-Mesyloxylated Products 2-Oxo-2-phenylethyl-4-Methanebenzenesulfonate (Entry 1) Solid; mp 90 °C (lit.5d 90-91 °C). IR (KBr): 1180, 1360, 1715 cm-1. 1H NMR (400 MHz, CDCl3): δ = 2.45 (s, 3 H), 5.27 (s, 2 H), 7.23-7.88 (m, 5 H) ppm.
2-Oxo-2-phenylethyl Methanesulfonate (Entry 1) Solid; mp 76-77 °C (lit.1a 76-78 °C). IR (KBr): νmax = 1725 cm-1. 1H NMR (60 MHz, CDCl3): δ = 3.20 (s, 3 H), 5.43 (s, 2 H), 7.12-8.12 (m, 5 H) ppm.
2-(4-Chlorophenyl)-2-oxo-ethyl 4-Methanebenzene-sulfonate (Entry 2) Solid; mp 123 °C (lit.6g 125 °C). IR (KBr): 1190, 1360, 1700 cm-1. 1H NMR (400 MHz, CDCl3): δ = 2.46 (s, 3 H), 5.21 (s, 2 H), 7.35 (d, J = 8.4 Hz, 2 H), 7.45 (d, J = 8.6 Hz, 2 H), 7.80 (d, J = 8.6 Hz, 2 H), 7.84 (d, J = 8.4 Hz, 2 H) ppm.
2-(2,4-Dichlorophenyl)-2-oxo-ethyl Methanesulfonate (Entry 3) Solid; mp 87 °C. IR (KBr): νmax = 1710 cm-1. 1H NMR (60 MHz, CDCl3): δ = 3.24 (s, 3 H), 5.44 (s, 2 H), 7.22-7.83 (m, 3 H) ppm. 13C NMR (300 MHz, CDCl3): δ = 37.65, 69.83, 128.90, 129.92, 130.46, 131.63, 136.10, 136.57, 190.74. Anal. Calcd (%) for C9H8Cl2O4S: C, 38.16; H, 2.82. Found: C, 38.15; H, 2.81.
2-(4-Nitrophenyl)-2-oxo-ethyl 4-Methanebenzene-sulfonate (Entry 4) Solid; mp 137 °C (lit.6g 130-131 °C). IR (KBr): 1180, 1340, 1710 cm-1. 1H NMR (400 MHz, CDCl3): δ = 2.47 (s, 3 H), 5.25 (s, 2 H), 7.37 (d, J = 8.3 Hz, 2 H), 7.83 (d, J = 8.3 Hz, 2 H), 8.03 (d, J = 8.9 Hz, 2 H), 8.32 (d, J = 8.9 Hz, 2 H) ppm.
2-Oxo-2- p -tolylethyl 4-Methylbenzenesulfonate (Entry 5) Solid; mp 80 °C (lit.6g 82-83 °C). IR (KBr): 1170, 1350, 1700 cm-1. 1H NMR (400 MHz, CDCl3): δ = 2.41 (s, 3 H), 2.45 (s, 3 H), 5.24 (s, 2 H), 7.26 (d, J = 8.1 Hz, 2 H), 7.35 (d, J = 8.2 Hz, 2 H), 7.74 (d, J = 8.1 Hz, 2 H), 7.86 (d, J = 8.2 Hz, 2 H) ppm.
2-Oxo-2- p -tolylethyl Methanesulfonate (Entry 5) IR (KBr): νmax = 1710 cm-1. 1H NMR (60 MHz, CDCl3): δ = 2.44 (s, 3 H), 3.28 (s, 3 H), 5.48 (s, 2 H), 7.28 (d, J = 8.33 Hz, 2 H), 7.77 (d, J = 8.33 Hz, 2 H) ppm. 13C NMR (300 MHz, CDCl3): δ = 190.68, 145.65, 130.93, 129.77, 127.86, 70.22, 39.27, 21.83. Anal. Calcd (%) for C10H12O4S: C, 52.63; H, 5.26. Found: C, 52.64; H, 5.25.
2-(4-Methoxyphenyl)-2-oxo-ethyl Methanesulfonate (Entry 6) Solid; mp 98 °C. IR (KBr): νmax 1710 cm-1. 1H NMR (60 MHz, CDCl3): δ = 3.22 (s, 3 H), 3.88 (s, 3 H), 5.44 (s, 2 H), 7.28 (d, J = 7.8 Hz, 2 H), 7.74 (d, J = 7.8 Hz, 2 H) ppm. 13C NMR (300 MHz, CDCl3): δ = 37.63, 70.35, 55.82, 114.24, 126.81, 129.86, 165.12, 190.92. Anal. Calcd (%) for C10H12O5S: C, 49.18; H, 4.91. Found: C, 49.20; H, 4.92.
2-[2-Chloro-4 (4-chlorophenoxy)phenyl]-2-oxo-ethyl Methanesulfonate (Entry 7) White solid; mp 118-119 °C. IR (KBr): νmax = 1715 cm-1. 1H NMR (60 MHz, CDCl3): δ = 3.20 (s, 3 H), 5.44 (s, 2 H), 7.20-7.89 (m, 7 H) ppm. 13C NMR (300 MHz, CDCl3): δ = 39.23, 73.64, 117.32, 121.62, 123.35, 124.14, 130.70, 130.73, 131.31, 132.32, 132.40, 158.12, 190.40. Anal. Calcd (%) for C15H13Cl2O5S: C, 47.87; H, 3.45. Found: C, 47.86; H, 3.42.
1-Oxo-1-phenylpropan-2-yl 4-Methanebenzenesulfonate (Entry 8) Solid; mp 68 °C (lit.6g 68-69 °C). IR (KBr): 1170, 1370, 1700 cm-1. 1H NMR (400 MHz, CDCl3): δ = 1.60 (d, J = 7.0 Hz, 3 H), 2.41 (s, 3 H), 5.79 (q, J = 7.0 Hz, 1 H), 7.29 (d, J = 8.1 Hz, 2 H), 7.46 (t, J = 7.2 Hz, 2 H), 7.60 (t, J = 7.2 Hz, 1 H), 7.75 (d, J = 7.2 Hz, 2 H), 7.88 (d, J = 8.1 Hz, 2 H) ppm.
2-(Furan-2-yl)-2-oxo-ethyl 4-Methanebenzensulfonate (Entry 9) Solid; mp 62 °C (lit.5e 65-67 °C). IR (KBr): νmax = 1670
cm-1. 1H NMR (60 MHz, CDCl3): δ = 3.27 (s, 3 H), 5.53 (s, 1 H), 7.28-8.05 (m, 3 H) ppm.
2-Oxo-cyclohexyl 4-Methylbenzenesulfonate (Entry 10) Solid; mp 76 °C (lit.5e 74-76 °C). IR (KBr): νmax = 1744
cm-1. 1H NMR (60 MHz, CDCl3): δ = 1.30-2.70 (m, 11 H), 4.82 (s, 1 H), 7.10 (d, 2 H), 8.02 (d, 2 H) ppm.
2-Oxo-propyl Methanesulfonate (Entry 11) Oil.1a IR (neat): νmax = 1738, 1367, 1187 cm-1. 1H NMR (60 MHz, CDCl3): δ = 2.20 (s, 3 H), 3.16 (s, 3 H), 4.37 (s, 2 H) ppm.
Ethyl 2-(Methylsulfonyloxy)-3-oxo-3-phenylpropanoate (Entry 15) Yellow oil.1a IR (KBr): νmax = 1670 cm-1. 1H NMR (60 MHz, CDCl3): δ = 1.13 (t, 3 H), 3.23 (s, 3 H), 4.24 (q, 2 H), 6.23 (s, 1 H), 7.23-8.20 (m, 5 H) ppm.