Supporting information. for. Highly Stereoselective Synthesis of Primary, Secondary and Tertiary -S-Sialosides under Lewis Acidic Conditions

Transcription

1 Supporting information for Highly Stereoselective Synthesis of Primary, Secondary and Tertiary -S-Sialosides under Lewis Acidic Conditions Amandine Noel, Bernard Delpech and David Crich * Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles, CNRS, 1 Avenue de la Terrasse, Gif-sur-Yvette, France, and b) Department of Chemistry, Wayne State University, Detroit, MI 48202, USA S1

2 Compound Expt Spectra Methyl 6-O-triphenylmethyl-α-D-galactopyranoside (22) S4 S16-17 Methyl 2,3,4-tri-O-benzyl- -D-galactopyranoside (1). S4 S18-19 Methyl 2,3,4-tri-O-benzyl-6-acetylthio- -D-galactopyranoside (2) S5 S20-21 Methyl 2,3,4-tri-O-benzyl-6-thio- -D-galactopyranoside (3) S6 S22-23 Methyl 4,6-O-benzylidene-2-O-benzoyl-β-D-gulopyranoside (5) S6 - Methyl 4,6-O-benzylidene-2-O-benzoyl-3-thioacetyl-β-D-galactopyranoside (6) S6 S24-25 Methyl 4,6-O-benzylidene-2-O-benzoyl-3-thio-β-D-galactopyranoside (7) S7 S26-27 Methyl 2,3,6-tri-O-benzyl-4-acetylthio- -D-galactopyranoside (9) S7 S28-29 Methyl 2,3,6-tri-O-benzyl-4-thio- -D-galactopyranoside (10) S8 S30-31 Methyl (5-acetamido-2-benzylthio-7,8,9-tri-O-acetyl-5-N,4-O-carbonyl-3,5- dideoxy-d-glycero- -D-galacto-non-2-ulopyranoside)onate (12) S9 S32-33 Methyl (5-acetamido-2-benzylthio-7,8,9-tri-O-acetyl-3,5-dideoxy-D-glyceroβ-D-galacto-non-2-ulopyranoside)onate (13) S9 S34-35 Methyl (5-acetamido-7,8,9-tri-O-acetyl-5-N,4-O-carbonyl-3,5-dideoxy-2-(4- methoxyphenyl)thio-d-glycero- -D-galacto-non-2-ulopyranoside)onate (14) S10 S36-37 Methyl (5-acetamido-7,8,9-tri-O-acetyl-5-N,4-O-carbonyl-3,5-dideoxy-2- tert-butylthio-d-glycero- -D-galacto-non-2-ulopyranoside)onate (15) S10 S38-39 Methyl (2-S-(methyl 2,3,4-tri-O-benzyl-6-thio- -D-galactopyranoside)-5-Nacetyl-7,8,9-tri-O-acetyl-5-N,4-O-carbonyl-3,5-dideoxy-D-glycero- -Dgalacto-non-2-ulopyranoside)onate S11 S40-41 (16) Methyl (2-S-(methyl 4,6-O-benzylidene-2-O-benzoyl-3-thio-β-D- galactothiopyranoside)-5-n-acetyl-7,8,9-tri-o-acetyl-5-n,4-o-carbonyl-3,5- S12 S42-43 dideoxy-d-glycero- -D-galacto-non-2-ulopyranoside)onate (17) Methyl (2-S-(methyl 2,3,6-tri-O-benzyl-4-thio- -D-galactopyranoside)-5-Nacetyl-7,8,9-tri-O-acetyl-5-N,4-O-carbonyl-3,5-dideoxy-D-glycero- -Dgalacto-non-2-ulopyranoside)onate S12 S44-45 (18) Methyl (2-S-(methyl 2,3,4-tri-O-benzyl-6-thio- -D-galactopyranoside)-5-Nacetyl-3,5-dideoxy-D-glycero- -D-galacto-non-2-ulopyranoside)onate (19) S13 S46-47 (2-S-(Methyl β-d-galactothiopyranoside)-5-n-acetyl-3,5-dideoxy-d-glyceroα-d-galacto-non-2-ulopyranoside)onic acid (20) S14 S48-49 Methyl (2-S-(methyl 2,3,6-tri-O-benzyl-4-thio- -D-galactopyranoside)-5-Nacetyl-3,5-dideoxy-D-glycero- -D-galacto-non-2-ulopyranoside)onate (21) S14 S50-51 S2

3 Reactions were performed using oven dried glasswares under an atmosphere of argon. All separations were carried out under flash-chromatographic conditions on silica gel (Redi Sep prepacked column, mesh) at medium pressure (20 psi) with use of a CombiFlash Companion. Reactions were monitored by thin-layer chromatography on Merck silica gel plates (60 F 254 aluminum sheets) which were rendered visible by ultraviolet light and/or spraying with phosphomolybdic acid (10%) in EtOH or vanillin (15%) + sulfuric acid (2.5%) in EtOH followed by heating. CH 3 CN, THF, DMF, CH 2 Cl 2 and MeOH were purchased from Acros Organics at the highest commercial quality and used without further purification. Reagent-grade chemicals were obtained from diverse commercial suppliers (Sigma-Aldrich, Acros Organics, TCI and Alfa-Aesar) and were used as received. 1 H NMR (500 or 300 MHz) and 13 C NMR (125 or 75 MHz) spectra were recorded on Bruker Avance spectrometers at 298 K unless otherwise stated. Chemical shifts are given in (δ) and are referenced to the internal solvent signal or to TMS used as an internal standard. Multiplicities are declared as follow: s (singlet), br s (broad singlet), d (doublet), t (triplet), q (quadruplet), dd (doublet of doublet), ddd (doublet of doublet of doublet), dt (doublet of triplet), m (multiplet). Coupling constants J are given in Hz. Carbon multiplicities were determined by DEPT135 experiment. Diagnostic correlations were obtained by twodimensional COSY, HSQC and HMBC experiments. Infrared spectra (IR) were recorded on a Perkin-Elmer FT-IR system using diamond window Dura SamplIR II and the data are reported in reciprocal centimeters (cm -1 ). Optical rotations were measured on a Anton Paar MCP 300 polarimeter at 589 nm. [ ] t C D is expressed in deg.cm 3.g -1.dm -1 and c is expressed in g/100 cm 3. Melting points were recorded in open capillary tubes on a Büchi B-540 apparatus and are uncorrected. High resolution mass spectra (HRMS) were recorded using a Micromass LCT Premier XE instrument (Waters) and were determined by electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI). S3

4 Methyl 2,3,4-Tri-O-benzyl- -D-galactopyranoside (1). Methyl 6-O-triphenylmethyl-α-D-galactopyranoside (22). To a solution of methyl- -Dgalactopyranoside (2 g, 10.3 mmol) in CH 2 Cl 2 (40 ml), were added DABCO (2.3 g, 20.5 mmol), followed by 96% TrCl (6.0 g, 20.6 mmol). The reaction mixture was stirred at room temperature for 4 h. The solvent was removed under vacuum. After purification on a silica cartridge (CH 2 Cl 2 /MeOH 9:1), the desired product was obtained as a white solid (4.0 g, 90%). Mp = C; [α] 20 D = (c 4.3, CHCl 3 ); IR υ max (cm -1 ): 3409; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 15 H), 4.74 (d, J = 3.3 Hz, 1 H), 4.41 (br s, 1 H), 3.89 (br s, 1 H), (m, 2 H), (m, 2 H), 3.44 (dd, J = 9.8, 6.6 Hz, 1 H), 3.39 (s, 3 H), 3.34 (br s, 1 H), 3.30 (dd, J = 9.8, 5.3 Hz, 1 H); 13 C NMR (75 MHz, CDCl 3 ): δ (3 C, C), (6 C, CH), (6 C, CH), (3 C, CH), 99.4 (CH), 86.8 (C), 70.7 (CH), 69.9 (CH), 69.3, 69.2 (2 C, CH), 63.3 (CH 2 ), 55.1 (CH 3 ); MS (ESI + ) m/z (%) (50, [M+Na] + ), (100, [2M+Na] + ); ESIHRMS calcd for C 26 H 28 NaO 6 (M+Na) , found Methyl 2,3,4-tri-O-benzyl- -D-galactopyranoside (1). To a solution of compound 22 (4.34 g, 9.94 mmol) in anhydrous DMF (38.2 ml), were added NaH 60% (3.2 g, 80.5 mmol), followed by benzyl bromide (7.1 ml, 59.7 mmol) and the reaction mixture was stirred overnight at room temperature. The reaction mixture was diluted with water and extracted with MTBE (methyl tert-butyl ether). The organic layer was washed with water, dried over Na 2 SO 4 and concentrated under vacuum. To a solution of the crude product in CH 2 Cl 2 (115 ml) were added at 0 C, Et 3 SiH (1.9 ml, 11.9 mmol) and TFA (4.7 ml) and the reaction mixture was stirred at this temperature for 1 h 30. The organic layer was washed with a saturated solution of NaHCO 3, extracted with CH 2 Cl 2, dried over Na 2 SO 4 and concentrated under vacuum. After purification on a silica cartridge (50:50 Heptane/AcOEt), the desired product was obtained as a colorless oil (3.31 g, 72%). [α] 20 D = 7.16 (c 1.9, CHCl 3 ); IR υ max (cm -1 ): 3474, 2902; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 15 H), 4.98 (d, J = 11.6 Hz, 1 H), 4.90 (d, J = 11.9 Hz, 1 H), 4.85 (d, J = 12.1 Hz, 1 H), 4.76 (d, J = 11.9 Hz, 1 H), 4.72 (d, J = 3.9 Hz, 1 H), 4.70 (d, J = 12.1 Hz, 1 H), 4.65 (d, J = 11.6 Hz, 1 H), 4.06 (dd, J = 10.0, 3.6 Hz, 1 H), 3.95 (dd, J = 10.0, 2.8 Hz, 1 H), 3.88 (br d, J = 2.8 Hz, 1 H), 3.73 (br s, 1 H), 3.72 (dd, J = 14.4, 6.5 Hz, 1 H), 3.49 (dd, J = 14.4, 8.0 Hz, 1 H), 3.37 (s, 3 H), 1.68 (br s, 1 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), (C), (C), (2 C, CH), (2 C, CH), (2 C, CH), (2 C, CH), (2 C, CH), (CH), (CH), (CH), (2 C, CH), 98.8 (CH), 79.1 (CH), 76.5 (CH), 75.1 (CH), S4

5 74.4 (CH 2 ), (CH 2 ), (CH 2 ), 70.2 (CH), 62.4 (CH 2 ), 55.4 (CH 3 ); MS (ESI + ) m/z (%) (100, [M+NH 4 ] + ), (40, [M+Na] + ), (30, [2M+Na] + ); ESIHRMS calcd for C 28 H 36 NO 6 (M+NH 4 ) , found Methyl 2,3,4-tri-O-benzyl-6-acetylthio- -D-galactopyranoside (2). To a solution of 1 (1.75 g, 3.77 mmol) in anhydrous THF (68.5 ml), were added, at 0 C, PPh 3 (1.98 g, 7.53 mmol), followed by DEAD (40% in hexane; 3.5 ml, 7.5 mmol) dropwise and the reaction mixture was stirred at this temperature for 30 min. Then, AcSH (0.54 ml, 7.5 mmol) was added and the reaction mixture was allowed to warm up to room temperature and stirred overnight. The reaction mixture was diluted with a saturated solution of NaHCO 3, the organic product was extracted with CH 2 Cl 2, which was dried over Na 2 SO 4 and concentrated under vacuum. After purification on a silica cartridge (70:30 Heptane/AcOEt), the desired product was obtained as a colorless oil (1.79 g, 91%). [α] 20 D = (c 0.48, CHCl 3 ); IR υ max (cm -1 ): 2906, 1690; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 15 H), 5.05 (d, J = 11.4 Hz, 1 H), 4.91 (d, J = 11.9 Hz, 1 H), 4.86 (d, J = 12.3 Hz, 1 H), 4.79 (d, J = 11.9 Hz, 1 H), 4.71 (d, J = 12.3 Hz, 1 H), 4.68 (d, J = 4.5 Hz, 1 H), 4.66 (d, J = 11.4 Hz, 1 H), 4.06 (dd, J = 9.9, 4.5 Hz, 1 H), 3.96 (dd, J = 9.9, 2.7 Hz, 1 H), 3.92 (dd, J = 2.7, 1.0 Hz, 1 H), 3.71 (ddd, J = 7.9, 5.9, 1.0 Hz, 1 H), 3.40 (s, 3 H), 3.09 (dd, J = 13.5, 7.9 Hz, 1 H), 3.00 (dd, J = 13.7, 5.9 Hz, 1 H), 2.33 (s, 3 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), (C), (2 C), (2 CH), (2 CH), (2 CH), (2 CH), (2 CH), (2 CH), (CH), (2 C, CH), 98.6 (CH), 79.1 (CH), 76.6 (CH), 76.1 (CH), 76.0 (CH), 74.7 (CH 2 ), (CH 2 ), (CH 2 ), 69.5 (CH), 55.1 (CH 3 ), 30.4 (CH 3 ), 29.9 (CH 2 ); MS (ESI + ) m/z (%) (100, [M+NH 4 ] + ), (40, [M+Na] + ); ESIHRMS calcd for C 30 H 38 NO 6 S (M+NH 4 ) , found Methyl 2,3,4-tri-O-benzyl-6-thio- -D-galactopyranoside (3). To a solution of 2 (41 mg, mmol) in anhydrous DMF (0.9 ml), was added hydrazine monohydrate (7 μl, 0.14 mmol) and the reaction mixture was stirred at room temperature for 10 min. Then acetic acid (8 μl, 0.14 mmol) was added and the reaction mixture was stirred at room temperature for 1 h. The reaction mixture was diluted with water and extracted with MTBE, which was dried over Na 2 SO 4 and concentrated under vacuum. After purification on a silica cartridge (80:20 Heptane/AcOEt), the desired product was obtained as a colorless oil (31.1 mg, 83%); [α] 20 D = (c 2.21, CHCl 3 ); IR υ max (cm -1 ): 2945, 2559; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 15 H), 5.00 (d, J = 11.6 Hz, 1 H), 4.91 (d, J = 11.6 Hz, 1 H), S5

6 4.85 (d, J = 12.2 Hz, 1 H), 4.78 (d, J = 11.6 Hz, 1 H), 4.69 (d, J = 12.2 Hz, 1 H), 4.67 (d, J = 3.9 Hz, 1 H), 4.66 (d, J = 11.6 Hz, 1 H), 4.05 (dd, J = 3.7, 1.0 Hz, 1 H), (m, 2 H), 3.65 (t, J = 6.8 Hz, 1 H), 3.40 (s, 3 H), 2.73 (ddd, J = 13.6, 7.4, 7.2 Hz, 1 H), 2.40 (ddd, J = 13.6, 10.3, 6.6 Hz, 1 H), 1.26 (dd, J = 10.2, 7.2 Hz, 1 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), (C), (C), (2 CH), (2 CH), (2 CH), (2 CH), (2 CH), (2 CH), (CH), (2 CH), 98.8 (CH), 79.4 (CH), 76.4 (CH), 74.8 (CH), 74.5 (CH 2 ), (CH 2 ), (CH 2 ), 72.3 (CH), 55.5 (CH 3 ), 24.9 (CH 2 ); MS (ESI + ) m/z (%) (100, [M+NH 4 ] + ), (80, [M+Na] + ); ESIHRMS calcd for C 28 H 36 NO 5 S (M+NH 4 ) , found Methyl 4,6-O-benzylidene-2-O-benzoyl-β-D-guloopyranoside (5). 1 To a solution of compound 4 2 (607.8 mg, 1.57 mmol) in CH 2 Cl 2 (12.1 ml) was added dry pyridine (0.98 ml, 12.1 mmol). The reaction mixture was cooled to 0 C and triflic anhydride (0.53 ml, 3.15 mmol) was added dropwise. The reaction mixture was allowed to warm up to room temperature and stirred for further 6 h. The reaction mixture was washed with saturated NaHCO 3 solution, dried over Na 2 SO 4 and the solvent was removed under vacuum. The triflate intermediate was obtained after purification on a silica gel cartridge (CH 2 Cl 2 ) as a white foam (774.7 mg, 95%). To a solution of this product (774 mg, 1.49 mmol) in CH 3 CN (10.5 ml) was added TBANO 2 (1.23 g, 4.25 mmol). The reaction mixture was stirred at room temperature overnight and the solvent was removed. Water was added and the organic product was extracted with AcOEt which was dried over Na 2 SO 4 and and concentrated under vacuum. The desired product was obtained after purification on a silica gel cartridge (95:5 CH 2 Cl 2 /AcOEt) as a yellow foam (387.1 mg, 63%). [α] 20 D = -1.2 (c 1, CHCl 3 ); IR υ max (cm - 1 ): 3505, 1731; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 2 H), (m, 8 H), 5.58 (s, 1 H), 5.37 (dd, J = 8.4, 3.2 Hz, 1 H), 4.98 (d, J = 8.4 Hz, 1 H), (m, 2 H), (m, 1 H), 4.11 (dd, J = 12.4, 1.9 Hz, 1 H), (m, 1 H), 3.57 (s, 3 H), 2.33 (br s, 1 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), (C), (C), (2 CH), (2 CH), (2 CH), (2 CH), (2 CH), (CH), 98.9 (CH), 76.2 (CH), 71.1 (CH), 69.4 (CH), 69.3 (CH 2 ), 65.7 (CH), 56.5 (CH 3 ); MS (ESI + ) m/z (%) (30, [M+NH 4 ] + ); ESIHRMS calcd for C 21 H 26 NO 7 (M+NH 4 ) , found Methyl 4,6-O-benzylidene-2-O-benzoyl-3-thioacetyl-β-D-galactopyranoside (6). S6

7 To a solution of 5 (510 mg, 1.32 mmol) in CH 2 Cl 2 (10.2 ml) was added dry pyridine (0.82 ml, 10.2 mmol). The reaction mixture was cooled to 0 C and triflic anhydride (0.44 ml, 2.64 mmol) was added dropwise. The reaction mixture was allowed to warm up to room temperature and stirred for further 6 h. The reaction mixture was washed with saturated NaHCO 3 solution, dried over Na 2 SO 4 and the solvent was removed under vacuum. The triflate intermediate was obtained after purification on a silica gel cartridge (CH 2 Cl 2 ) as a yellow syrup (643 mg, 94%). To a solution of this intermediate (643 mg, 1.24 mmol) in DMF (4.1 ml) was added KSAc (425.2 mg, 3.72 mmol). The reaction mixture was stirred at 60 C for 5 h. Water was added and the organic product was extracted with MTBE which was dried over Na 2 SO 4, filtered and the solvent was removed under vacuum. The desired product was obtained, after purification on a silica gel cartridge (80:20 Heptane/AcOEt), as a yellowish foam (380.6 mg, 69%). [α] 20 D = 97.5 (c 1.89, CHCl 3 ); IR υ max (cm -1 ): 2866, 1727, 1697; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 2 H), (m, 8 H), 5.56 (s, 1 H), 5.45 (dd, J = 11.5, 7.9 Hz, 1 H), 4.65 (d, J = 7.9 Hz, 1 H), 4.39 (dd, J = 12.5, 1.4 Hz, 1 H), 4.25 (dd, J = 11.5, 3.4 Hz, 1 H), 4.14 (dd, J = 3.4, 0.8 Hz, 1 H), 4.10 (dd, J = 12.5, 1.8 Hz, 1 H), (m, 1 H), 3.51 (s, 3 H), 2.20 (s, 3 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), (C), (C), (C), (2 CH), (2 CH), (2 CH), (2 CH), (2 CH), (CH), (CH), 75.9 (CH), (CH 2 ), (CH), 68.5 (CH), 56.4 (CH 3 ), 46.9 (CH), 30.5 (CH 3 ); MS (ESI + ) m/z (%) (100, [M+NH 4 ] + ); ESIHRMS calcd for C 23 H 28 NO 7 S (M+NH 4 ) , found Methyl 4,6-O-benzylidene-2-O-benzoyl-3-thio-β-D-galactopyranoside (7). To a solution of 6 (200 mg, 0.45 mmol) in DMF (3.8 ml) was added hydrazine acetate (62.2 mg, 0.67 mmol). The reaction mixture was stirred at room temperature for 2 h. Water was added and the organic product was extracted with MTBE which was dried over Na 2 SO 4, filtered and the solvent was removed under vacuum. The desired product was obtained, after purification on a silica gel cartridge (70:30 Heptane/AcOEt), as a yellowish foam (173.9 mg, 96%). [α] 20 D = 79.9 (c 1.11, CHCl 3 ); IR υ max (cm -1 ): 2923, 2500, 1723; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 2 H), (m, 8 H), 5.60 (s, 1 H), 5.33 (dd, J = 11.2, 7.9 Hz, 1 H), 4.53 (d, J = 7.9 Hz, 1 H), 4.38 (dd, J = 12.5, 1.4 Hz, 1 H), 4.16 (dd, J = 3.2, 0.9 Hz, 1 H), 4.11 (dd, J = 12.5, 1.9 Hz, 1 H), (m, 1 H), 3.51 (s, 3 H), 3.14 (td, J = 11.0, 3.2 Hz, 1 H), 2.22 (d, J = 10.8 Hz, 1 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), (2 C), (CH), (2 CH), (CH), ( CH), (CH), (2 CH), (2 CH), (CH), (CH), 76.6 (CH), 72.4 (CH), (CH 2 ), (CH), 56.3 (CH 3 ), 43.8 (CH); MS (ESI + ) m/z (%) (100, [M+NH 4 ] + ); ESIHRMS calcd for C 21 H 26 NO 6 S (M+NH 4 ) , found Methyl 2,3,6-tri-O-benzyl-4-acetylthio- -D-galactopyranoside (9). S7

8 To a solution of 8 3 (221 mg, 0.48 mmol) in anhydrous THF (2.8 ml), was added 1 M NaHMDS in THF (0.57 ml, 0.57 mmol) at -78 C and the reaction mixture was stirred at this temperature for 30 min. Comin s reagent (224.2 mg, 0.57 mmol) was added and the reaction mixture was stirred at -78 C for 1 h 30. Water was added and the organic product was extracted with CH 2 Cl 2 which was dried over Na 2 SO 4 and concentrated under vacuum. To a solution of the crude material in DMF (2.4 ml) was added AcSK (108.7 mg, 0.95 mmol) and the reaction was stirred at room temperature overnight. Water was added and the organic product was extracted with CH 2 Cl 2 which was dried over Na 2 SO 4 and concentrated under vacuum. The desired product was obtained after purification on a silica cartridge (80:20 Heptane/AcOEt) as a colorless oil (149.9 mg, 60%); [α] 20 D = (c 0.91, CHCl 3 ); IR υ max (cm -1 ): 2908, 1694; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 15 H), 4.86 (d, J = 12.0 Hz, 1 H), 4.68 (d, J = 11.2 Hz, 1H), 4.63 (J = 12.0 Hz, 1 H), 4.63 (d, J = 3.7 Hz, 1 H), 4.56 (d, J = 11.2 Hz, 1 H), 4.54 (d, J = 12.0 Hz, 1 H), 4.47 (dd, J = 4.5, 1.6 Hz, 1 H), 4.46 (d, J = 12.0 Hz, 1 H), 4.30 (ddd, J = 6.7, 5.1, 1.6 Hz, 1 H), 4.17 (dd, J = 10.0, 4.5 Hz, 1 H), 3.59 (dd, J = 10.0, 6.7 Hz, 1 H), 3.52 (dd, J = 10.0, 5.2 Hz, 1 H), 3.46 (dd, J = 10.0, 3.7 Hz, 1 H), 3.39 (s, 3 H), 2.37 (s, 3 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), (C), (C), (C), (2 CH), (2 CH), (2 CH), (2 CH), (2 CH), (CH), (CH), (CH), (CH), (CH), 98.9 (CH), 77.6 (CH), 76.4 (CH), 73.8 (CH 2 ), 73.5 (CH 2 ), 72.1 (CH 2 ), 70.6 (CH 2 ), 68.1 (CH), 55.4 (CH 3 ), 47.4 (CH), 31.0 (CH 3 ); MS (ESI + ) m/z (%) (60, [M+NH 4 ] + ), (100, [M+Na] + ), (30, [2M+Na] + ); ESIHRMS calcd for C 30 H 34 NaO 6 S (M+Na) , found Methyl 2,3,6-tri-O-benzyl-4-thio- -D-galactopyranoside (10). To a solution of 9 (48.5 mg, mmol) in anhydrous DMF (1 ml), was added hydrazine monohydrate (8 μl, 0.16 mmol) and the reaction mixture was stirred at room temperature for 10 min. Then acetic acid (9 μl, 0.16 mmol) was added and the reaction mixture was stirred at room temperature for 1 h. To the reaction mixture was added water and the organic product was extracted with MTBE which was dried over Na 2 SO 4 and concentrated under vacuum. After purification on a silica cartridge (80:20 Heptane/AcOEt), the desired product was obtained as a colorless oil (42.5 mg, 95%); [α] 20 D = (c 0.92, CHCl 3 ); IR υ max (cm -1 ): 2906, 2505; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 15 H), 4.78 (d, J = 11.9 Hz, 1 H), 4.62 (br s, 2 H), 4.59 (J = 11.9 Hz, 1 H), 4.57 (d, J = 3.1 Hz, 1 H), 4.52 (d, J = 11.8 Hz, 1 H), 4.46 (d, J = 11.8 Hz, 1 H), 4.12 (td, J = 6.1, 1.9 Hz, 1 H), 3.95 (dd, J = 9.9, 4.4 Hz, 1 H), 3.85 (dd, J = 9.9, 3.1 Hz, 1 H), (m, 1 H), 3.55 (d, J = 6.3 Hz, 2 H), 3.31 (s, 3 H), 1.60 (d, J = 5.7 Hz, 1 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), (C), (C), (3 S8

9 CH), (3 CH), (3 CH), (3 CH), (3 CH), 98.9 (CH), 76.8 (CH), 75.5 (CH), 73.7 (CH 2 ), 73.6 (CH 2 ), 71.9 (CH 2 ), 70.4 (CH 2 ), 67.6 (CH), 55.2 (CH 3 ), 42.9 (CH); MS (ESI + ) m/z (%) (60, [M+NH 4 ] + ), (100, [M+Na] + ), (20, [2M+Na] + ); ESIHRMS calcd for C 28 H 32 NaO 5 S (M+Na) , found General procedure for S-glycosylation with a sialyl phosphate donor: A solution of sialyl phosphate donor 11α,β, 4 acceptor (2 equiv. or 1.2 equiv.) with pulverized 4 Å MS (2 g.mmol -1 ) in dry CH 2 Cl 2 (0.04 M) or CH 2 Cl 2 /CH 3 CN (2:1) (0.04 M) was stirred under argon at room temperature for 2 h. The reaction mixture was then cooled to -78 C followed by addition of TMSOTf (1 equiv.). After being stirred at the same temperature for 1.25 h the reaction mixture was quenched with triethylamine (2 equiv), diluted with CH 2 Cl 2 and filtered through a pad of Celite. The filtrate was washed with brine, dried over Na 2 SO 4, filtered and concentrated under vacuum. Methyl (5-acetamido-2-benzylthio-7,8,9-tri-O-acetyl-5-N,4-O-carbonyl-3,5-dideoxy-Dglycero- -D-galacto-non-2-ulopyranoside)onate (12). This compound was prepared according to the general procedure for S-glycosylation with a sialyl phosphate donor from sialyl α-phosphate 11α (40 mg, 0.06 mmol) and benzyl mercaptan (14 µl, 0.12 mmol) in CH 2 Cl 2 (0.65 ml). Purification on a silica cartridge by HPLC (70:30 Heptane/AcOEt) gave the desired products as a colorless oil (12.1 mg, 80%, 83% brsm ); [α] 20 D = (c 0.46, CHCl 3 ); IR υ max (cm -1 ): 2955, 1796, 1738; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 5 H), 5.61 (dd, J = 7.0, 1.5 Hz, 1 H), 5.52 (ddd, J = 7.0, 6.7, 2.6 Hz, 1 H), (m, 1 H), 4.42 (dd, J = 9.4, 1.5 Hz, 1 H), 4.14 (dd, J = 12.4, 6.7 Hz, 1 H), 3.97 (d, J = 13.7 Hz, 1 H), 3.91 (ddd, J = 12.0, 11.0, 3.5 Hz, 1 H), 3.85 (d, J = 13.7 Hz, 1 H), 3.72 (dd, J = 11.0, 9.4 Hz, 1 H), 3.52 (s, 3 H), 3.03 (dd, J = 12.0, 3.5 Hz, 1 H), 2.48 (s, 3 H), 2.18 (s, 3 H), 2.17 (s, 3 H), 2.11 (t, J = 12.4 Hz, 1 H), 2.02 (s, 3 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), (C), (C), (C), (C, 3 J C-H3ax. = 7.0 Hz), (C), (C), (2 CH), (2 CH), (CH), 83.6 (C), 76.8 (CH), 75.8 (CH), 72.3 (CH), 69.8 (CH), 62.9 (CH 2 ), 59.3 (CH), 53.0 (CH 3 ), 36.5 (CH 2 ), 33.2 (CH 2 ), 24.7 (CH 3 ), 21.3 (CH 3 ), 21.0 (CH 3 ), 20.8 (CH 3 ); MS (ESI + ) m/z (%) (100, [M+NH 4 ] + ); ESIHRMS calcd for C 26 H 35 N 2 O 12 S (M+ NH 4 ) , found Methyl (5-acetamido-2-benzylthio-7,8,9-tri-O-acetyl-3,5-dideoxy-D-glycero-β-D-galactonon-2-ulopyranoside)onate (13). S9

10 This compound was prepared according to the general procedure for S-glycosylation with a sialyl phosphate donor from sialyl α-phosphate 11α (39 mg, mmol) and benzyl mercaptan (5 equiv., 34.3 µl, 0.29 mmol) in CH 2 Cl 2 (0.65 ml). Purification on a silica cartridge by HPLC (70:30 Heptane/AcOEt) gave 13 as a colorless oil (25.3 mg, 78%); [α] 20 D = (c 0.87, CHCl 3 ); IR υ max (cm -1 ): 3362, 2956, 1743, 1658; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 5 H), 5.31 (dd, J = 6.1, 2.2 Hz, 1 H), 5.20 (ddd, J = 7.0, 6.1, 2.4 Hz, 1 H), 5.11 (br d, J = 10.0 Hz, 1 H), 4.43 (dd, J = 12.4, 2.4 Hz, 1 H), (m, 2 H), 4.00 (dd, J = 12.4, 7.0 Hz, 1 H), (m, 1 H), 3.85 (s, 3 H), 3.78 (d, J = 12.6 Hz, 1 H), 3.69 (d, J = 12.6 Hz, 1 H), 3.04 (td, J = 12.0, 4.7 Hz, 1 H), 2.33 (t, J = 13.4 Hz, 1 H), 2.23 (dd, J = 13.4, 4.7 Hz, 1 H), 2.13 (s, 3 H), 2.07 (s, 3 H), 2.04 (s, 3 H), 1.92 (s, 3 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), (C), (C), (C), (C, 3 J C-H3ax. 0 Hz), (C), (2 CH), (2 CH), (CH), 94.3 (C), 71.7 (CH), 70.8 (CH), 68.5 (CH), 62.7 (CH 2 ), 53.5 (CH 3 ), 48.6 (CH), 42.7 (CH), 38.3 (CH 2 ), 34.1 (CH 2 ), 23.3 (CH 3 ), 21.0, 20.9, 20.8 (3 CH 3 ); MS (ESI + ) m/z (%) (100, [M+H] + ), (30, [2M+Na] + ); ESIHRMS calcd for C 25 H 34 NO 11 S (M+H) , found Methyl (5-acetamido-7,8,9-tri-O-acetyl-5-N,4-O-carbonyl-3,5-dideoxy-2-(4- methoxyphenyl)thio-d-glycero- -D-galacto-non-2-ulopyranoside)onate (14). This compound was prepared according to the general procedure for S-glycosylation with a sialyl phosphate donor from sialyl α-phosphate 11α (49.2 mg, mmol) and 4- methoxybenzenethiol (18 µl, 0.15 mmol) in CH 2 Cl 2 (1.85 ml). Purification on a silica cartridge by HPLC (60:40 Heptane/AcOEt) gave the desired product as a white foam (32.2 mg, 73%); [α] 20 D = 6.7 (c 2.25, CHCl 3 ); IR υ max (cm -1 ): 2955, 1796, 1738; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 2 H), (m, 2 H), 5.52 (dd, J = 6.0, 1.5 Hz, 1 H), 5.32 (ddd, J = 6.8, 6.0, 2.9 Hz, 1 H), 4.41 (dd, J = 12.2, 2.9, 1 H), 4.31 (dd, J = 9.5, 1.5 Hz, 1 H), 4.19 (dd, J = 12.2, 6.8 Hz, 1 H), 3.94 (ddd, J = 12.6, 11.2, 3.6 Hz, 1 H), 3.82 (s, 3 H), 3.62 (s, 3 H), 3.58 (dd, J = 11.2, 9.4 Hz, 1 H), 3.08 (dd, J = 12.1, 3.6 Hz, 1 H), 2.45 (s, 3 H), 2.16 (s, 3 H), (s, 3 H), (s, 3 H), 2.08 (dd, J = 12.6, 12.1 Hz, 1 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), (C), (C), (C), (C, 3 J C-H3ax. = 7.6 Hz), (C), (C), (2 CH), (C), (2 CH), 87.7 (C), 77.3 (CH), 75.8 (CH), 72.6 (CH), 70.6 (CH), 62.6 (CH 2 ), 59.1 (CH), 55.4 (CH 3 ), 53.1 (CH 3 ), 36.5 (CH 2 ), 24.7 (CH 3 ), 21.1 (CH 3 ), 20.9 (CH 3 ), 20.8 (CH 3 ); MS (ESI + ) m/z (%) (100, [M+NH 4 ] + ), (90, [M+Na] + ), (30, [2M+Na] + ); ESIHRMS calcd for C 26 H 35 N 2 O 13 S (M+ NH 4 ) , found Methyl (5-acetamido-7,8,9-tri-O-acetyl-5-N,4-O-carbonyl-3,5-dideoxy-2-tert-butylthio-Dglycero- -D-galacto-non-2-ulopyranoside)onate (15). S10

11 This compound was prepared according to the general procedure for S-glycosylation with a sialyl phosphate donor from sialyl α-phosphate 11α (47.9 mg, mmol) and tert-butyl mercaptan (16 µl, 0.14 mmol) in CH 2 Cl 2 (1.8 ml). Purification on a silica cartridge by HPLC (60:40 Heptane/AcOEt) gave the desired products as a white foam (35.1 mg, 89%); [α] 20 D = 27.1 (c 0.55, CHCl 3 ); IR υ max (cm -1 ): 1796, 1737; 1 H NMR (300 MHz, CDCl 3 ): δ 5.58 (dd, J = 7.6, 1.3 Hz, 1 H), 5.43 (ddd, J = 7.6, 6.4, 2.6 Hz, 1 H), 4.51 (dd, J = 9.5, 1.3 Hz, 1 H), 4.37 (dd, J = 12.3, 2.6 Hz, 1 H), 4.11 (dd, J = 12.3, 6.4 Hz, 1 H), 3.86 (ddd, J = 12.7, 11.3, 3.5 Hz, 1 H), 3.81 (s, 3 H), 3.68 (dd, J = 11.3, 9.5 Hz, 1 H), 3.01 (dd, J = 12.0, 3.5 Hz, 1 H), 2.48 (s, 3 H), 2.16 (s, 3 H), 2.14 (s, 3 H), 2.03 (s, 3 H), (m, 1 H), 1.37 (s, 9 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), (2 C), (C), (C, 3 J C-H3ax. = 5.8 Hz), (C), 85.3 (C), 76.6 (C), 75.5 (CH), 72.1 (CH), 70.1 (CH), 62.6 (CH 2 ), 59.5 (CH), 53.1 (CH 3 ), 48.5 (C), 38.5 (CH 2 ), 31.6 (3 CH 3 ), 24.8 (CH 3 ), 21.1 (CH 3 ), 20.9 (CH 3 ), 20.7 (CH 3 ); MS (ESI + ) m/z (%) (100, [M+NH 4 ] + ), (30, [M+Na] + ); ESIHRMS calcd for C 23 H 37 N 2 O 12 S (M+NH 4 ) , found Methyl (2-S-(methyl 2,3,4-tri-O-benzyl-6-thio- -D-galactopyranoside)-5-N-acetyl-7,8,9- tri-o-acetyl-5-n,4-o-carbonyl-3,5-dideoxy-d-glycero- -D-galacto-non-2- ulopyranoside)onate (16). This compound was prepared according to the general procedure for S-glycosylation with a sialyl phosphate donor from sialyl α-phosphate 11α (50 mg, mmol) and 3 (43.2 mg, mmol) in CH 2 Cl 2 (1.9 ml). Purification on a silica gel cartridge (70:30 Heptane/AcOEt) gave the desired product as colorless oil (39.2 mg, 56%, 70% brsm); [α] 20 D = (c 1.0, CHCl 3 ); IR υ max (cm -1 ): 2929, 1797, 1740; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 15 H), 5.64 (dd, J = 8.7, 1.1 Hz, 1 H), 5.41 (ddd, J = 8.5, 5.7, 2.8 Hz, 1 H), 5.02 (d, J = 10.9 Hz, 1 H), (d, J = 11.9 Hz, 1 H), (d, J = 12.4 Hz, 1 H), 4.79 (d, J = 12.4 Hz, 1 H), 4.75 (d, J = 10.9 Hz, 1 H), 4.67 (d, J = 11.9 Hz, 1 H), 4.62 (d, J = 3.7 Hz, 1 H), 4.33 (dd, J = 12.9, 2.8 Hz, 1 H), 4.29 (dd, J = 9.5, 1.1 Hz, 1 H), 4.05 (dd, J = 12.9, 5.7 Hz, 1H), (m, 2 H), 3.89 (ddd, J = 14.8, 11.0, 3.5 Hz, 1 H), 3.85 (dd, J = 10.2, 2.8 Hz, 1 H), 3.74 (s, 3 H), 3.65 (dd, J = 11.0, 9.5 Hz, 1 H), 3.50 (dd, J = 9.1, 3.9 Hz, 1 H), 3.38 (s, 3 H), (m, 3 H), 2.49 (s, 3 H), 2.14 (s, 3 H), 2.13 (s, 3 H), 2.05 (dd, J = 10.8, 3.5 Hz, 1 H), 1.96 (s, 3 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), (C), (C), (C), (C, 3 J C-H3ax. = 5.7 Hz), (C), (C), (C), (C), (3 CH), (3 CH), (3 CH), (2 CH), (2 CH), (2 CH), 98.9 (CH), 82.7 (C), 79.0 (CH), 77.2 (CH), S11

12 76.1, 75.98, (3 CH), 74.9 (CH 2 ), 73.6 (CH 2 ), 72.9 (CH 2 ), 71.5 (CH), 69.8 (CH), 68.6 (CH), 62.7 (CH 2 ), 59.3 (CH), 55.4 (CH 3 ), 53.1 (CH 3 ), 36.4 (CH 2 ), 30.0 (CH 2 ), 24.7 (CH 3 ), 21.4 (CH 3 ), 21.0 (CH 3 ), 20.7 (CH 3 ); MS (ESI + ) m/z (%) (80, [M+NH 4 ] + ), (100, [M+Na] + ); ESIHRMS calcd for C 47 H 55 NNaO 17 S (M+Na) , found Methyl (2-S-(methyl 4,6-O-benzylidene-2-O-benzoyl-3-thio-β-D-galactopyranoside)-5-N- acetyl-7,8,9-tri-o-acetyl-5-n,4-o-carbonyl-3,5-dideoxy-d-glycero- -D-galacto-non-2- ulopyranoside)onate (17). This compound was prepared according to the general procedure for S-glycosylation with a sialyl phosphate donor from sialyl α-phosphate 11α (52.3 mg, mmol) and 7 (37.8 mg, mmol) in CH 2 Cl 2 /CH 3 CN (2:1) (1.8 ml). Purification on a silica gel cartridge (60:40 Heptane/AcOEt) gave the desired product as a white foam (57.7 mg, 86%); [α] 20 D = (c 0.13, CHCl 3 ); IR υ max (cm -1 ): 1736; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 2 H), (m, 8 H), 5.65 (ddd, J = 9.9, 6.7, 2.4 Hz, 1 H), 5.54 (dd, J = 9.9, 1.4 Hz, 1 H), 5.46 (s, 1 H), 5.23 (dd, J = 11.8, 7.6 Hz, 1 H), 4.90 (d, J = 7.6 Hz, 1 H), 4.51 (dd, J = 12.3, 2.4 Hz, 1 H), 4.36 (dd, J = 12.3, 1.2 Hz, 1 H), 4.28 (dd, J = 9.4, 1.4 Hz, 1 H), 4.11 (dd, J = 12.3, 6.7 Hz, 1 H), 4.06 (dd, J = 12.3, 2.4 Hz, 1 H), 3.89 (dd, J = 11.8, 3.3 Hz, 1 H), (m, 2 H), 3.77 (s, 3 H), (m, 1 H), (m, 1 H), 3.50 (s, 3 H), 2.93 (dd, J = 12.1, 3.3 Hz, 1 H), 2.45 (s, 3 H), 2.21 (s, 3 H), 2.09 (s, 3 H), (m, 1 H), 1.46 (s, 3 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), (C), (C), (C), (C, 3 J C-H3ax. = 7.2 Hz), (C), (C), (C), (C), (CH), (2 CH), (CH), (2 CH), (2 CH), (2 CH), (CH), (CH), 81.7 (C), (CH), (CH), (CH), 71.2 (CH), 69.2 (CH 2 ), 69.0 (CH), 68.0 (CH), 67.7 (CH), 63.5 (CH 2 ), 58.9 (CH), 56.7 (CH 3 ), 53.1 (CH 3 ), 45.7 (CH), 35.9 (CH 2 ), 24.6 (CH 3 ), 21.6 (CH 3 ), 20.9 (CH 3 ), 20.4 (CH 3 ); MS (ESI + ) m/z (%) (100, [M+NH 4 ] + ); ESIHRMS calcd for C 40 H 49 N 2 O 18 S (M+NH 4 ) , found Methyl (2-S-(methyl 2,3,6-tri-O-benzyl-4-thio- -D-galactopyranoside)-5-N-acetyl-7,8,9- tri-o-acetyl-5-n,4-o-carbonyl-3,5-dideoxy-d-glycero- -D-galacto-non-2- ulopyranoside)onate (18). S12

13 This compound was prepared according to the general procedure for S-glycosylation with a sialyl phosphate donor from sialyl α-phosphate 11α (40 mg, mmol) and 10 (34.6 ml, mmol) in CH 2 Cl 2 (1.5 ml). Purification on a silica gel cartridge (70:30 Heptane/AcOEt) gave the desired product as colorless oil (37.7 mg, 67%, 92% brsm; [α] 20 D = (c 1.91, CHCl 3 ); IR υ max (cm -1 ): 2924, 1796, 1744; 1 H NMR (300 MHz, CDCl 3 ): δ (m, 15 H), 5.54 (dd, J = 8.7, 1.1 Hz, 1 H), 5.37 (ddd, J = 8.7, 5.9, 3.0 Hz, 1 H), 4.98 (d, J = 11.4 Hz, 1 H), 4.77 (d, J = 11.7 Hz, 1 H), 4.76 (d, J = 11.4 Hz, 1 H), (m, 4 H), 4.44 (dd, J = 9.7, 1.1 Hz, 1 H), (m, 2 H), 4.14 (dd, J = 9.7, 4.3 Hz, 1H), 4.01 (dd, J = 12.3, 5.8 Hz, 1 H), (m, 5 H), 3.69 (s, 3 H), 3.39 (s, 3 H), 3.20 (dd, J = 11.0, 9.7 Hz, 1 H), (m, 2 H), 2.48 (s, 3 H), 2.12 (s, 3 H), 1.99 (s, 3 H); 13 C NMR (75 MHz, CDCl 3 ): δ (C), 170.5, 169.9, (3 C), (C, 3 J C-H3ax. = 6.6 Hz), (C), (C), (C), (C), (2 CH), (2 CH), (2 CH), (2 CH), (2 CH), (2 CH), (CH), (CH); (CH), 98.0 (CH), 82.3 (C), 78.9 (CH), 76.6 (CH), 75.3 (CH 2 ), 74.5 (CH 2 ), 73.3 (CH 2 ), 73.2 (CH 2 ), 71.9 (CH), 71.6 (CH), 70.2 (2 CH), 68.9 (CH), 62.7 (CH 2 ), 58.6 (CH), 55.2 (CH 3 ), 53.2 (CH 3 ), 48.0 (CH), 38.5 (CH 2 ), 24.7 (CH 3 ), 21.1 (CH 3 ), 20.9 (CH 3 ), 20.7 (CH 3 ); MS (ESI + ) m/z (%) (40, [M+NH 4 ] + ), (100, [M+HCOOH] + ); ESIHRMS calcd for C 47 H 59 N 2 O 17 S (M+NH 4 ) , found General procedure for the selective cleavage of the O-acetyl bonds and of the oxazolidinone ring: To a solution of sialoside (1 equiv.) in MeOH (0.05 M) were added few drops of 20 wt% sodium methoxide in MeOH and the mixture was stirred at room temperature for 30 min followed by treatment with Amberlyst 15 ion-exchange resin for 5 min. The mixture was diluted with MeOH and filtered through a sintered funnel containing Celite. The pad was rinsed with MeOH after filtration. The filtrate was concentrated under vacuum and passed through a reverse phase GracePure C18 cartridge (water and then MeOH) to afford the deprotected N-acetamidosialosides without further purification. Methyl (2-S-(methyl 2,3,4-tri-O-benzyl-6-thio- -D-galactopyranoside)-5-N-acetyl-3,5- dideoxy-d-glycero- -D-galacto-non-2-ulopyranoside)onate (19). This compound was prepared according to the general procedure for the selective saponification from 16 (29 mg, mmol) and MeONa in MeOH (0.62 ml). The desired product was obtained as a colorless oil (23.7 mg, 98%); [α] 20 D = 45.9 (c 2.15, CH 3 OH); IR υ max (cm -1 ): , 2921, 1716; 1 H NMR (300 MHz, CD 3 OD): δ (m, 15 H), 4.96 (d, J = 11.0 Hz, 1 H), 4.85 (d, J = 11.7 Hz, 1 H), 4.79 (d, J = 11.7 Hz, 1 H), 4.78 (d, J = 11.5 Hz, 1 H), 4.71 (d, J = 3.6 Hz, 1 H), 4.69 (d, J = 11.7 Hz, 1 H), 4.63 (d, J = 11.0 Hz, 1 H), 4.24 (br s, 1 H), (m, 2 H), (m, 3 H), 3.84 (s, 3 H), (m, 3 H), (m, 1 H), 3.48 (dd, J = 10.3, 1.4 Hz, 1 H), 3.41 (s, 3 H), (m, 3 H), 2.04 (s, S13

14 3 H), 1.84 (dd, J = 12.7, 11.5 Hz, 1 H); 13 C NMR (75 MHz, CD 3 OD): δ (C), (C, 3 J C-H3ax. = 7.3 Hz), (C), (C), (C), (2 CH), (2 CH), (2 CH), (2 CH), (2 CH), (2 CH), (CH), (2 CH), (CH), 85.1 (C), 80.2, 77.41, (3 CH), 76.9 (CH), 76.2 (CH 2 ), 74.3 (CH 2 ), 73.9 (CH 2 ), 72.5 (CH), 71.3 (CH), 69.9 (CH), 68.9 (CH), 64.5 (CH 2 ), 55.9 (CH 3 ), 53.7 (CH), 53.6 (CH 3 ), 42.1 (CH 2 ), 31.3 (CH 2 ), 22.7 (CH 3 ); MS (ESI + ) m/z (%) (100, [M+NH 4 ] + ), (80, [M+Na] + ); ESIHRMS calcd for C 40 H 55 N 2 O 13 S (M+NH 4 ) , found (2-S-(Methyl β-d-galactothiopyranoside)-5-n-acetyl-3,5-dideoxy-d-glycero-α-d-galactonon-2-ulopyranoside)onic acid (20). To a solution of compound 17 (20 mg, mmol) in MeOH (0.34 ml) was added NaOH (9.3 mg, 0.23 mmol) in water (0.12 ml). The reaction mixture was stirred at room temperature overnight. Dowex 50W X8, acidic resin was added. After filtration on a sintered funnel, the filtrate was concentrated under vacuum and passed through a reverse phase GracePure C18 cartridge (water then MeOH). The solvent was removed and the product was dissolved in D 2 O for overnight NMR experiments. The solvent was removed under vacuum and the crude product was passed through a reverse phase GracePure C18 cartridge (water). The solvent was removed to give the desired product as a white foam (9 mg, 77%); [α] 20 D = (c 0.90, H 2 O); IR υ max (cm -1 ): 3306, 1730; 1 H NMR (300 MHz, D 2 O): δ 4.44 (d, J = 7.1 Hz, 1 H), 5.46 (s, 3 H), (m, 4 H), (m, 3 H), (m, 1 H), 3.60 (s, 3 H), (m, 2 H), 2.84 (dd, J = 12.7, 4.8 Hz, 1 H), 2.05 (s, 3 H), 1.89 (dd, J = 12.7, 11.5 Hz, 1 H); 13 C NMR (75 MHz, D 2 O): δ (C), (C, 3 J C-H3ax. = 7.5 Hz), (CH), 83.2 (C), 77.3 (CH), 75.0 (CH), 71.6 (CH), 68.7 (CH), (CH), (CH), 68.1 (CH), 62.8 (CH 2 ), 61.1 (CH 2 ), 57.0 (CH 3 ), 51.6 (CH), 50.9 (CH), 40.3 (CH 2 ), 22.1 (CH 3 ); MS (ESI - ) m/z (%) (100, [M-H] - ); ESIHRMS calcd for C 18 H 30 NO 13 S (M-H) , found Methyl (2-S-(methyl 2,3,6-tri-O-benzyl-4-thio- -D-galactopyranoside)-5-N-acetyl-3,5- dideoxy-d-glycero- -D-galacto-non-2-ulopyranoside)onate (21). This compound was prepared according to the general procedure for the selective cleavage of oxazolidinones from 18 (47.6 mg, mmol) and MeONa in MeOH (1 ml). The desired product was obtained as a colorless oil (31.7 mg, 79%); [α] 20 D = 24.6 (c 2.5, CH 3 OH); IR υ max (cm -1 ): 3391, 2929; 1 H NMR (300 MHz, CD 3 OD): δ (m, 15 H), 4.98 (d, J = S14

15 12.1 Hz, 1 H), 4.72 (d, J = 11.8 Hz, 1 H), 4.68 (d, J = 3.0 Hz, 1H), 4.62 (d, J = 12.1 Hz, 1 H), 4.63 (d, J = 12.4 Hz, 1 H), 4.64 (d, J = 11.8 Hz, 1 H), 4.55 (d, J = 12.4 Hz, 1H), 4.18 (ddd, J = 4.9, 4.9, 2.2 Hz, 1 H), 4.07 (dd, J = 9.6, 4.1 Hz, 1 H), (m, 2 H), (m, 2 H), 3.77 (s, 3 H), (m, 1 H), (m, 6 H), 3.36 (s, 3 H), 2.81 (dd, J = 12.2, 4.7 Hz, 1 H), 2.16 (dd, J = 13.2, 11.3 Hz, 1 H), 2.04 (s, 3 H); 13 C NMR (75 MHz, CD 3 OD): δ (C), (C, 3 J C-H3ax. = 7.6 Hz), (2 C), (C), (2 CH), (2 CH), (2 CH), (2 CH), (2 CH), (CH), (CH), (CH), (2 CH), 99.2 (CH), 84.0 (C), 78.8 (CH), 78.0 (CH), 77.5 (CH), 74.3 (2 CH 2 ), 74.2 (CH 2 ), 73.8 (CH 2 ), 72.4 (CH), 71.2 (CH), 70.3 (CH), 70.0 (CH), 64.7 (CH 2 ), 55.7 (CH 3 ), 53.8 (CH 3 ), 53.6 (CH), 47.9 (CH), 30.7 (CH 2 ), 22.6 (CH 3 ); MS (ESI + ) m/z (%) (100, [M+NH 4 ] + ), (70, [M+Na] + ); ESIHRMS calcd for C 40 H 55 N 2 O 13 S (M+NH 4 ) , found (1) Busse, H.; Hakoda, M.; Stanley, M.; Streicher, H. r. J. Carbohydr. Chem. 2007, 26, 159. (2) Dang, N.; Munasinghe, V. R. N.; Overend, W. G. J. Chem. Soc. Perkin Trans , 257. (3) Shie, C. R.; Tzeng, Z. H.; Kulkarni, S. S.; Uang, B. J.; Hsu, C. Y.; Hung, S. C. Angew. Chem. Int. Ed. 2005, 44, (4) Noel, A.; Delpech, B.; Crich, D. Org. Lett. 2012, 14, S15

16 0,9 2,0 1,9 2,0 S16 2,5 2 15,3 7,190 7,205 7,215 7,223 7,238 7,260 7,267 7,287 7,293 7,310 7,316 7,459 7,470 7,487 7,494 7,499 4,749 4,760 4,415 3,279 3,296 3,306 3,311 3,329 3,343 3,386 3,417 3,438 3,449 3,471 3,706 3,730 3,798 3,817 3,837 3,889 8,5 8 7,5 7 1 H NMR (300 MHz, CDCl 3) of compound 22 6,5 6 5,5 5 4,5 4 3,5 3

17 S , , , ,586 99,449 86,767 76,594 77,016 77,438 69,155 69,286 69,875 70,748 63,331 55, C NMR (75 MHz, CDCl 3) of compound

18 S18 15,2 7,260 7,277 7,293 7,300 7,306 7,311 7,325 7,335 7,343 7,348 7,354 7,367 7,372 7,394 7,401 7,410 7,429 7,0 2,0 3,371 3,478 3,499 3,684 3,706 3,731 3,879 3,888 3,928 3,937 3,961 3,971 4,042 4,054 4,075 4,087 4,628 4,666 4,683 4,710 4,723 4,740 4,779 4,833 4,873 4,884 4,923 4,963 5,002 1,1 1, ,5 7 6,5 6 1 H NMR (300 MHz, CDCl 3) of compound 1 5,5 5 4,5 4 3,5 3 2,5 2 1,5

19 S , , , , , , , , , , , ,571 98,831 70,239 73,591 73,620 74,435 75,096 76,478 76,594 77,016 77,445 79,117 62,400 55, C NMR (75 MHz, CDCl 3) of compound

20 S20 7,455 15,0 7,260 7,288 7,304 7,311 7,316 7,329 7,335 7,343 7,349 7,358 7,365 7,370 7,379 7,384 7,390 7,405 7,412 7,417 7,423 7,426 7,448 7,0 3,1 4,638 4,676 4,692 4,734 4,769 4,808 4,838 4,878 4,892 4,932 5,032 5,070 3,398 3,691 3,711 3,715 3,719 3,909 3,913 3,919 3,922 3,936 3,969 3,978 4,038 4,050 4,071 4,083 2,0 2, ,125 2,9 2,325 7,5 7 6,5 6 5,5 1 H NMR (300 MHz, CDCl 3) of compound 2 5 4,5 4 3,5 3 2,5 2

21 S21 195, , , , , , , , , , ,613 98,605 69,461 73,373 73,438 74,682 75,991 76,078 76,594 77,016 77,438 79,088 55,129 29,867 30, C NMR (75 MHz, CDCl 3) of compound

22 S22 0,7 2,0 6,0 15,7 1,1 1,228 1,252 1,262 1,286 1,568 2,312 2,351 2,373 2,386 2,397 2,408 2,419 2,431 2,453 2,680 2,704 2,728 2,749 2,773 3,399 3,626 3,649 3,933 3,951 3,960 4,021 4,024 4,032 4,036 4,057 4,060 4,069 4,637 4,661 4,675 4,715 4,760 4,799 4,827 4,867 4,892 4,931 4,985 5,023 7,260 7,273 7,288 7,296 7,301 7,311 7,314 7,322 7,335 7,340 7,349 7,354 7,363 7,368 7,374 7,387 7,396 7,401 7,409 7,415 7,435 7, ,5 1 1,5 2 2,5 3 3,5 4 4,5 5 5,5 6 6,5 7 7,5 8 1 H NMR (300 MHz, CDCl 3) of compound 3

23 S , , , , , , , , , , ,586 98,809 72,319 73,584 73,613 74,544 74,769 76,383 76,587 77,016 77,438 79,416 55,456 24, C NMR (75 MHz, CDCl 3) of compound

24 0,9 2,0 S24 2,0 8,0 7,260 7,365 7,372 7,381 7,389 7,406 7,409 7,433 7,460 7,519 7,526 7,534 7,539 7,552 7,559 7,984 7,989 8,013 5,295 5,416 5,442 5,454 5,480 5,561 3,504 3,714 3,718 4,080 4,086 4,121 4,127 4,140 4,149 4,150 4,228 4,239 4,266 4,277 4,365 4,370 4,407 4,412 4,638 4,665 2,198 8,5 8 7,5 7 6,5 6 1 H NMR (300 MHz, CDCl 3) of compound 6 5,5 5 4,5 4 3,5 3 2,5 2 1,5

25 S , , , , , , , , , ,161 68,493 68,951 68,987 75,867 76,594 77,016 77,438 56,369 46,908 30, C NMR (75 MHz, CDCl 3) of compound

26 2,0 S26 2,0 8,0 7,260 7,377 7,383 7,393 7,401 7,415 7,431 7,455 7,460 7,477 7,482 7,541 7,548 7,553 7,558 7,565 7,576 8,057 8,062 8,082 8,086 8,089 5,599 5,302 5,328 5,339 5,365 4,085 4,091 4,126 4,132 4,154 4,157 4,165 4,168 4,359 4,363 4,400 4,405 4,518 4,544 3,502 3,620 3, ,110 3,136 3,146 3,172 3,183 2,200 2, ,5 7 6,5 6 1 H NMR (300 MHz, CDCl 3) of compound 7 5,5 5 4,5 4 3,5 3 2,5 2

27 S , , , , , , , , , ,594 77,016 77,438 72,384 68,952 69,010 56,321 43, C NMR (75 MHz, CDCl 3) of compound

28 7,1 2,0 S28 16,6 7,358 7,345 7,339 7,331 7,319 7,311 7,303 7,299 7,295 7,290 7,281 7,273 7,260 3,388 3,435 3,448 3,468 3,481 3,495 3,512 3,528 3,546 3,564 3,586 3,597 3,620 4,150 4,165 4,183 4,198 4,300 4,439 4,464 4,471 4,479 4,485 4,524 4,537 4,564 4,574 4,611 4,620 4,633 4,652 4,664 4,702 4,835 4,875 2,369 7,5 7 6,5 6 5,5 1 H NMR (300 MHz, CDCl 3) of compound 9 5 4,5 4 3,5 3 2,5 2

29 S29 194, , , , , , , , , , , , ,454 98,882 68,109 70,596 72,123 73,548 73,825 76,428 76,617 77,039 77,460 77,591 55,377 47,400 30, C NMR (75 MHz, CDCl 3) of compound

30 6,0 2,9 3,1 S30 1 0,5 15,7 7,176 7,198 7,213 7,219 7,226 7,242 7,250 7,260 7,269 7,276 7,288 7,298 7,303 7,309 7,315 7,335 7,341 3,312 3,539 3,552 3,559 3,831 3,843 3,864 3,876 3,926 3,940 3,959 3,973 4,115 4,122 4,437 4,476 4,501 4,541 4,569 4,579 4,611 4,620 4,758 4,798 1,591 1, ,5 7 6,5 6 5,5 1 H NMR (300 MHz, CDCl 3) of compound ,5 4 3,5 3 2,5 2 1,5

31 S31 137, , , , , , , ,382 98,867 70,421 71,868 73,569 73,707 75,489 76,594 76,841 77,016 77,445 67,643 55,230 42, C NMR (75 MHz, CDCl 3) of compound

32 2,0 2,9 S32 6,3 7,220 7,242 7,260 7,267 7,292 7,308 7,314 7,335 5,513 5,523 5,536 5,545 5,608 5,614 5,632 5,638 3,526 3,682 3,713 3,719 3,751 3,835 3,867 3,880 3,909 3,957 4,002 4,113 4,134 4,154 4,176 4,402 4,408 4,433 4,439 4,442 4, ,482 6,0 2,020 2,042 2,070 2,111 2,152 2,169 2,175 1, ,5 6,5 6 5,5 1 H NMR (300 MHz, CDCl 3) of compound ,5 4 3,5 3 2,5 2 1,5

33 S33 168, , , , , , , , , ,087 83,619 69,751 72,311 75,787 76,587 76,791 77,016 77,438 62,936 59, ,457 33,236 20,763 20,967 21,250 24, C NMR (75 MHz, CDCl 3) of compound

34 S34 7,2 2,0 2,0 1,915 2,019 2,027 2,041 2,071 2,129 2,212 2,242 2,257 2,289 2,330 2,375 2, ,670 3,713 3,763 3,805 3,852 3,880 3,917 3,968 3,991 4,009 4,032 4,106 4,119 4,126 4,130 4,153 4,160 4,405 4,413 4,446 4,454 5,097 5,130 5,170 5,178 5,192 5,198 5,214 5,222 5,295 5,302 5,315 5,322 7,237 7,251 7,260 7,266 7,279 7,293 7,302 7,306 7,310 7,317 1,5 2 2,5 3 3,5 4 4,5 5 5,5 6 6,5 7 7,5 1 H NMR (300 MHz, CDCl 3) of compound 13

35 S35 169, , , , , , , , ,037 94,309 76,610 77,031 77,453 68,473 70,814 71,738 62,765 53,486 48,643 42,753 38,340 34,108 20,808 20, , C NMR (75 MHz, CDCl 3) of compound

36 4,0 7,0 S36 1,9 7,260 7,433 7,440 7,455 7,462 2,0 6,846 6,853 6,868 6,875 5,304 5,316 5,325 5,325 5,337 5,347 5,510 5,515 5,530 5, ,103 3,543 3,574 3,580 3,612 3,622 3,816 3,897 3,909 3,935 3,939 3,947 3,951 3,977 3,989 4,157 4,180 4,198 4,220 4,292 4,297 4,323 4,328 4,388 4,397 4,428 4,438 2,449 2,043 2,065 2,068 2,084 2,125 2,159 7,5 7 6,5 6 1 H NMR (300 MHz, CDCl 3) of compound 14 5,5 5 4,5 4 3,5 3 2,5 2 1,5

37 S37 168, , , , , , , , , ,493 87,676 70,639 72,602 75,794 76,594 77,016 77,321 77,445 62,575 59, ,354 36,455 20,836 20, , C NMR (75 MHz, CDCl 3) of compound

38 1,2 3,9 2,8 6,9 2,9 S38 1 0,5 0 0,8 7,260 2,987 2, ,641 3,673 3,678 3,710 3,813 3,828 3,842 3,859 3,866 3,870 3,896 3,908 4,082 4,103 4,123 4,144 4,344 4,353 4,385 4,394 4,493 4,496 4,497 4,524 4,528 5,400 5,410 5,425 5,430 5,434 5,446 5,455 5,562 5,562 5,566 5,587 5,591 2,483 2,028 2,037 2,103 2,119 2,142 2,156 2,185 8,9 1, ,5 1 H NMR (300 MHz, CDCl 3) of compound ,5 5 4,5 4 3,5 3 2,5 2 1,5

39 S39 169, , , , ,443 85,307 70,071 72,085 75,489 76,594 76,681 77,016 77,438 62,573 59, ,479 38,508 31,643 20,720 20,923 21,134 24, C NMR (75 MHz, CDCl 3) of compound

40 S40 14,9 4,0 1,1 2,0 1,1 6,0 2,0 1,959 2,017 2,045 2,052 2,094 2,127 2,143 2,485 2, ,382 3,475 3,487 3,506 3,518 3,619 3,652 3,655 3,688 3,737 3,830 3,839 3,850 3,863 3,872 3,891 3,900 3,963 3,975 3,989 4,010 4,021 4,038 4,060 4,080 4,274 4,277 4,304 4,311 4,344 4,354 4,612 4,624 4,646 4,687 4,737 4,754 4,774 4,794 4,823 4,835 4,862 5,007 5,043 5,396 5,405 5,415 5,425 5,434 5,444 5,628 5,632 5,657 5,661 7,245 7,260 7,278 7,302 7,318 7,324 7,332 7,342 7,364 7,376 7,394 7,402 1,5 2 2,5 3 3,5 4 4,5 5 5,5 6 6,5 7 7,5 1 H NMR (300 MHz, CDCl 3) of compound 16

41 S41 168, , , , , , , , , , , , , , ,353 98,877 59,315 62,653 68,551 69,838 71,489 72,914 73,620 74,885 75,918 75,983 76,063 76,594 77,016 77,249 77,438 79,030 82,689 55, ,399 30,014 20,712 20,996 21,381 24, C NMR (75 MHz, CDCl 3) of compound

42 S42 4,0 3,8 2,0 2,0 1,9 7,7 2,9 2,8 2,8 1,461 1,600 2,044 2,085 2,092 2,127 2,205 2,446 2,903 2,914 2,943 2,954 3,478 3,504 3,510 3,516 3,548 3,662 3,673 3,770 3,786 3,812 3,823 3,861 3,872 3,900 3,911 4,041 4,046 4,076 4,082 4,087 4,098 4,116 4,139 4,266 4,271 4,297 4,303 4,334 4,339 4,375 4,380 4,489 4,498 4,531 4,539 4,887 4,913 5,200 5,226 5,239 5,265 5,296 5,461 5,522 5,527 5,554 5,560 5,616 5,625 5,639 5,647 7,260 7,344 7,354 7,360 7,368 7,380 7,396 7,432 7,456 7,482 7,526 7,532 7,539 7,544 7,549 7,559 7,568 8,151 8,156 8, ,5 2 2,5 3 3,5 4 4,5 5 5,5 6 6,5 7 7,5 8 1 H NMR (300 MHz, CDCl 3) of compound 17

43 S43 165, , , , , , , , , , , , , , , , ,685 56,656 58,924 63,455 67,723 68,036 68,959 69,177 71,213 75,794 75,809 75,845 76,594 77,016 77,438 81,735 53,129 45,712 35,946 20,378 20,851 21,571 24, C NMR (75 MHz, CDCl 3) of compound

44 S44 6,0 2,0 4,0 16,7 2,0 8,0 2,0 1,988 2,123 2,479 2,722 2,764 2,767 2,782 3,170 3,202 3,207 3,239 3,393 3,691 3,697 3,707 3,739 3,752 3,766 3,776 3,781 3,977 3,997 4,018 4,038 4,116 4,130 4,149 4,163 4,281 4,291 4,321 4,331 4,423 4,427 4,455 4,459 4,591 4,601 4,607 4,640 4,647 4,652 4,745 4,750 4,783 4,789 4,958 4,996 5,337 5,347 5,357 5,366 5,376 5,385 5,395 5,524 5,529 5,554 5,557 5,557 7,242 7,253 7,260 7,267 7,272 7,281 7,283 7,293 7,300 7,307 7,316 7,324 7,337 7,343 7,347 7, ,5 1 1,5 2 2,5 3 3,5 4 4,5 5 5,5 6 6,5 7 7,5 8 8,5 9 1 H NMR (300 MHz, CDCl 3) of compound 18

45 S45 169, , , , , , , , , , , , , , , , , ,620 98,031 58,575 62,677 68,865 70,246 71,599 71,948 73,191 73,264 74,471 75,344 76,594 76,660 77,016 77,438 78,914 82,339 53,194 55,201 48,010 38,513 20,662 20,858 21,127 24, C NMR (75 MHz, CDCl 3) of compound

46 S46 6,0 6,0 2,6 15,0 2,0 1,795 1,833 1,838 1,876 2,036 2,765 2,781 2,807 2,824 2,829 2,844 2,867 3,329 3,334 3,340 3,345 3,351 3,415 3,463 3,467 3,497 3,502 3,543 3,547 3,574 3,577 3,663 3,677 3,678 3,686 3,698 3,715 3,830 3,839 3,847 3,960 3,968 4,237 4,608 4,645 4,702 4,715 4,760 4,807 4,830 4,870 4,944 4,981 7,297 7,311 7,315 7,325 7,339 7,343 7,350 7,363 7,370 7,393 7,397 7,437 7,440 7,462 1,5 2 2,5 3 3,5 4 4,5 5 5,5 6 6,5 7 7,5 1 H NMR (300 MHz, CD 3OD) of compound 19

47 S47 175, , , , , , , , , , , , ,105 99,952 64,452 68,902 69,862 71,295 72,480 73,883 74,334 76,166 76,915 77,359 77,417 80,202 85,110 42,136 48,433 48,716 49,000 49,284 49,567 53,647 53,748 55,872 31,308 22, C NMR (75 MHz, CD 3OD) of compound

48 4,0 4,0 2,0 S48 1,6 1,4 4,780 4,433 4,447 3,368 3,374 3,385 3,399 3,584 3,597 3,657 3,660 3,663 3,675 3,678 3,681 3,687 3,741 3,746 3,757 3,764 3,775 3,866 3,867 3,871 3,872 3,880 3,886 3,900 3,908 3,920 2,822 2,831 2,847 2,857 2,5 2,054 1,866 1,891 1,914 5,2 5 4,8 4,6 4,4 1 H NMR (300 MHz, D 2O) of compound 20 4,2 4 3,8 3,6 3,4 3,2 3 2,8 2,6 2,4 2,2 2 1,8