Synlett 2022(16): 2461-2464  
DOI: 10.1055/s-2005-872701
LETTER
© Georg Thieme Verlag Stuttgart · New York

Phosphomolybdic Acid Supported on Silica Gel: An Efficient, Mild and Reusable Catalyst for the Chemoselective Hydrolysis of Acetonides

J. S. Yadav*, S. Raghavendra, M. Satyanarayana, E. Balanarsaiah
Division of Organic Chemistry, Indian Institute of Chemical Technology, Hyderabad-500 007, India
Fax: +91(410)7160387; e-Mail: yadavpub@iict.res.in;
Further Information

Publication History

Received 26 May 2005
Publication Date:
21 September 2005 (online)

Abstract

Carbohydrate acetonides were chemoselectively cleaved to the corresponding diols by using environmentally benign phosphomolybdic acid (H3PMo12O40) supported on silica gel (PMA-SiO2) at ambient temperature in a short span of 5-7 minutes in acetonitrile. Acid-labile protective groups such as THP, TBS, TBDPS, MOM, OMe and PMB were found to be stable under the reaction conditions.

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Typical Experimental Procedure. (a) Preparation of PMA/SiO 2 Catalyst. PMA-SiO2 catalyst was prepared following the published procedure. [11]
(b) Preparation of Terminal Diols. To a solution of glucose diacetonide (260 mg, 1 mmol) in MeCN (2 mL) were added the 1 mol% PMA/SiO2 (0.01 mmol, based on PMA) followed by 40 µL of H2O, and the reaction mixture was stirred at ambient temperature for 5-7 min. After completion of the reaction as indicated by TLC, the solvent was removed under reduced pressure and the residue was dissolved in THF (2 mL) and filtered. The filtrate was concentrated under reduced pressure and purified by column chromatography (100-200 silica gel mesh) using hexane and EtOAc as solvent system to afford the pure diols. The filtered catalyst was reused without prior drying.
Spectral Data.
Entry b: [α]D +6 (c 1.76, CHCl3). 1H NMR (200 MHz, CDCl3): δ = 7.38 (s, 5 H), 5.75 (d, J = 3.8 Hz, 1 H), 4.64 (dd, J 1,2 = J 2,3 = 3.7 Hz, 1 H), 4.54 (s, 2 H), 3.40-4.00 (m, 6 H), 2.00-2.40 (m, 1 H), 1.48 (s, 3 H), 1.29 (s, 3 H). MS-FAB: m/z = 325.
Entry c: [α]D +2.8 (c 1, MeOH). 1H NMR (200 MHz, CDCl3): δ = 7.78 (d, J = 8.0 Hz, 2 H), 7.38 (d, J = 8.0 Hz, 2 H), 4.83 (d, J = 7.0 Hz, 1 H), 4.15 (d, J = 5.5 Hz, 1 H), 4.05 (d, J = 5.5 Hz, 1 H), 3.90 (d, J = 5.0 Hz, 1 H), 3.52-3.70 (m, 2 H), 2.60 (br s, 1 H), 2.50 (s, 3 H), 2.00 (br s, 1 H), 1.50 (s, 3 H), 1.32 (s, 3 H). MS-FAB: m/z = 389 [M+ + 1].
Entry d: [α]D -16.2 (c 0.4, CHCl3). 1H NMR (200 MHz, CDCl3): δ = 7.35-7.24 (m, 5 H), 6.98-6.82 (m, 1 H), 5.85 (d, J = 15.6 Hz, 1 H), 4.69 (d, J = 11.1 Hz, 1 H), 4.46 (d, J = 11.1 Hz, 1 H), 4.18 (q, J = 7.4 Hz, 2 H), 3.86-3.78 (m, 2 H), 3.50 (dd, J 1,2 = 11.1, J 2,3 = 5.9 Hz, 1 H), 3.35 (dd, J 1,2 = 11.1 Hz, J 2,3 = 5.9 Hz, 1 H), 2.52 (t, J = 6.7 Hz, 2 H), 1.58-1.43 (m, 2 H), 1.28 (t, J = 7.4 Hz, 3 H). MS-FAB: m/z = 331 [M+ + 23], 309 [M+ + 1].