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Synlett 2007(9): 1467-1469  
DOI: 10.1055/s-2007-980348
LETTER
© Georg Thieme Verlag Stuttgart · New York

Traces of Water as a Key Parameter for the Formation of an Epoxydithio Compound

Aline Bancheta, Stéphane Guillarmeb, Arnaud Haudrechy*a
a Laboratoire de Glycosynthèse, UMR 6519, UFR Sciences Exactes et Naturelles, Bât. 18, BP 1039, 51687 Reims Cedex 2, France
Fax: +33(3)26913166; e-Mail: arnaud.haudrechy@univ-reims.fr;
b UCO2M, UMR CNRS 6011, Faculté des Sciences, Av. Olivier Messiaen, 72085 Le Mans Cedex 9, France
Further Information

Publication History

Received 6 March 2007
Publication Date:
23 May 2007 (online)

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Abstract

The presence of a small amount of water has proven to be necessary in order to obtain a reproducible amount of an epoxydithio compound. Conversely, under anhydrous conditions, an interesting thiosugar derivative results from a selective internal attack of sulfur, followed by an ‘ethyl’ transfer.

Key words

carbohydrates - epoxides - ring closure - sulfur - water

4

Experimental procedure for 3: Compound 1 (780 mg, 1.1 mmol) was treated at 0 °C with KOH (123 mg, 2.2 mmol) in dry MeOH (11 mL). The solution was stirred at r.t. for 12 h. The solvent was then removed under reduced pressure and the residue was washed with H2O and Et2O. The organic layer was dried over MgSO4 and evaporated. The crude product was purified by silica gel column chromatography (pentane-EtOAc, 9:1) to give the β-thiosugar 3 (506 mg, 0.94 mmol, 85%). IR (film): 3087, 3063, 3029, 2963, 2923, 2869, 1496, 1454, 1373, 1264, 1207, 1072, 1028, 735, 698 cm-1; 1H NMR (500 MHz, CDCl3): δ = 7.2-7.4 (m, 15 H), 4.98 (d, J = 1.2 Hz, 1 H), 4.26-4.64 (6 d, J = 11.8, 12.1, 12.1, 11.8, 12.3, 12.3 Hz, 6 H), 3.97 (ddd, J = 2.1, 9.0, 9.7 Hz, 1 H), 3.67 (dd, J = 2.9, 3.2 Hz, 1 H), 3.62 (dd, J = 2.9, 9.7 Hz, 1 H), 3.58 (dd, J = 1.2, 3.2 Hz, 1 H), 2.85 (dd, J = 2.1, 14.0 Hz, 1 H), 2.73 (q, J = 7.5 Hz, 2 H), 2.64 (m, 3 H), 1.32 (t, J = 7.5 Hz, 3 H), 1.23 (t, J = 7.5 Hz, 3 H); 13C NMR (125 MHz, CDCl3): δ = 137.7-138.1, 127.8-128.4, 82.0, 78.2, 76.9, 75.7, 73.6, 72.8, 72.3, 71.5, 33.6, 27.2, 25.7, 15.3, 15.0; HRMS (ESI): m/z [M + Na] calcd for C31H38O4NaS2: 561.2109; found: 561.2103. Anal. Calcd for C31H38O4S2: C, 69.11; H, 7.12. Found: C, 69.23; H, 7.42. (The β-con-figuration was determined by ROESY).

6

In reference 2g, Krohn and Boerner added water to their reaction mixture in order to obtain an epoxydithio compound without any discussion on this particular point.

7

Experimental procedure for 2: Compound 1 (120 mg, 0.170 mmol) was treated at 0 °C with KOH (19.7 mg, 0.34 mmol) in MeOH-H2O (1.7 mL, 99:1). The solution was stirred at r.t. for 3 h. The solvent was then removed under reduced pressure and the residue was washed with H2O and Et2O. The organic layer was dried (MgSO4) and evaporated to give the crude epoxydithio compound 2 (90.6 mg, 0.167 mmol, 98%). IR (film): 3088, 3063, 3030, 2964, 2923, 2868, 1732, 1497, 1455, 1357, 1264, 1208, 1070, 846, 734, 698 cm-1; 1H NMR (500 MHz, CDCl3): δ = 7.40-7.26 (m, 15 H), 4.90-4.73 (4d, J = 10.9, 11.1, 11.1, 10.9 Hz, 4 H), 4.66 (2d, J = 11.9, 11.9 Hz, 2 H), 4.54 (d, J = 12.0 Hz, 1 H), 4.23 (dd, J = 3.2, 6.8 Hz, 1 H), 4.01 (dd, J = 4.0, 6.8 Hz, 1 H), 3.93 (d, J = 4.0 Hz, 1 H), 3.42 (dd, J = 3.2, 5.7 Hz, 1 H), 3.39-3.34 (m, 1 H), 2.78-2.57 (m, 6 H), 1.20 (t, J = 1.2 Hz, 6 H); 13C NMR (125 MHz, CDCl3): δ = 138.6, 138.2, 138.1, 128.3, 128.1, 128.0, 127.9, 127.6, 127.5, 127.4, 127.3, 82.9, 82.3, 78.7, 75.6, 75.1, 72.3, 53.6, 50.7, 45.2, 25.4, 24.9, 14.5, 14.3; HRMS (ESI): m/z [M + Na] calcd for C31H38O4NaS2: 561.2109; found: 561.2111.