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89 Chemical synthesis of sulfoglycolipid analog SM1a-core3 4 2,2,2-Trichloroace�midate 2,3,4,6-tetra- O -benzoyl-α-D-galactopyranoside (5). Compound 5 was synthesized as described before. 33 Dimethylthexylsilyl 4,6- O -benzylidene-2-[(2,2,2-trichloroethoxy)carbonylamino]-β-D- galactopyranoside (6). Compound 6 was synthesized as described before. 32 Scheme S3. Chemical glycosyla�on of galactose donor 5 and galactosamine acceptor 6 to form disaccharide 12 . Selec�ve opening of the benzylidene acetal and subsequent acetyla�on provided disaccharide 10 .Removalofanomericprotec�ngroup(TDS)andforma�onoftheace�midateprovided disaccharide donor 3 . Reagents and condi�ons: (a) TMSOTf, CH 2 Cl 2 , 4 Å MS, -40 °C; (b) i. i) Cl 2 BPh, Et 3 SiH, CH 2 Cl 2 , 4 ÅMS, -68 °C, ii. Ac 2 O, Pyridine; (c) i. HF·Pyridine, Pyr, ii. ClC(NPh)CF 3 , Cs 2 CO 3 , CH 2 Cl 2 . Dimethylthexylsilyl 2,3,4,6-tetra- O -benzoyl-β-D-galactopyranosyl-(1→3)-4,6- O - benzylidene-2-[(2,2,2-trichloroethoxy)carbonylamino]-β-D-galactopyranoside (12). A mixture of acceptor 6 (300 mg, 0.51 mmol), donor 5 (570 mg, 0.77 mmol) and 4 Å molecular sieves was s�rred in DCM (5 mL) for 2.5 h. The mixture was cooled to -40 °C and TMSOTf (18 µL, 0.10 mmol) was added. A�er 10 min Et 3 N/MeOH was added and the mixture was concentrated in vacuo . The obtained residue was purified by silica column chromatography using Toluene:EtOAc (1:0 to 100:4 v/v) as the eluent to afford compound 12 (256 mg, 43 %) . 1 H NMR (600 MHz, CDCl 3 ) δ 8.11 – 7.12 (m, 25H, H-Ar), 5.96 (1H, s, H-4, Gal-V), 5.82 (1H, t, J = 9.1 Hz, H-2, Gal-V), 5.54 (1H, d, J = 10.3 Hz, H-3, Gal-V), 5.49 – 5.43 (1H, m, C H -C 6 H 5 ), 5.11 – 5.00 (2H, m, H-1, Gal-V; H-1; GalNAc-IV), 4.75 (1H, dd, J = 11.0, 7.3 Hz, H-6a, Gal-V), 4.60 – 4.52 (2H, m, H-3, GalNAc-IV; CH H , Troc), 4.42 – 4.30 (3H, m, H-6b, Gal-V; H-5, Gal-V; H-4, GalNAc-IV), 4.11 (1H, d, J = 12.1 Hz, H-6a, GalNAc-IV), 3.99 (1H, d, J = 12.0 Hz, CH H , Troc), 3.74 (1H, d, J = 12.0 Hz, H-6b, GalNAc-IV), 3.42 – 3.33 (1H m, H-2, GalNAc-IV), 3.20 (1H, s, H-5, GalNAc-IV), 1.63 – 1.55 (1H, m, C H -TDS), 0.85 – 0.76 (12H, m, J = 19.8, 6.0 Hz, 4x CH 3 , TDS), 0.14 (3H, s, CH 3 -Si), 0.08 (3H, s, CH 3 -Si). 13 C NMR (151 MHz, CDCl 3 ) δ 166.0 (C=O, Bz), 165.6 (C=O, Bz), 165.6 (C=O, Bz), 165.0 (C=O, Bz), 153.7 (C=O, Troc), 133.6 (C, Bz), O BzO OBz BzO BzO O CCl 3 NH O O O HO TrocHN OTDS Ph O O O O TrocHN O BzO OBz BzO BzO OTDS Ph O BnO OAc O TrocHN O BzO OBz BzO BzO OTDS O BnO OAc O TrocHN O BzO OBz BzO BzO O CF 3 NPh O O O HO TrocHN OTDS Ph O BzO OBz BzO BzO O CCl 3 NH + a b c 5 6 12 , 43% 10 , 55% 3 , 62% O O O O TrocHN O BzO OBz BzO BzO OTDS Ph