Hydrogenolysis reactions of disaccharides 30 and 33

2.9 Synthesis of disaccharides using desymmetric aminoprotecting strategy

At present, we had developed the desymmetric aminoprotecting strategy. The scope of investigation included the installation, deprotection, and application to glycosylations. At this stage, we focused on the removal of the oxazolidinone ring in disaccharide 16. It seemed that basic condition (t-BuOK/DMSO) at room temperature would be practical (Table 10, entry 5), but it didn’t proceed. The reaction outcome was not reproducible, and more intriguingly, the installation of Cbz protecting group failed when the residue was treated with NaHCO3 in MeOH, followed by benzyloxycarbonyl chloroformate (Scheme 23). What we could do was using the other basic conditions (1,4-dioxane/1M NaOH, v/v = 1:1) which was also feasible for the monosaccharide 19 (Table 10, entry 4). Fortunately, the removal of the oxazolidinone ring was successful and further installation of Cbz protecting group furnished desymmetric protected disaccharide 38 in high yield.

CbzCl, NaHCO₃ MeOH, rt, 82%

Scmeme 23. Removal studies of the N-benzyl oxazolidinone ring in disaccharides 16

2.10 Synthesis of trisaccharide 41 via one-pot glycosylation and deprotection

After some experimentation, the key component of disaccharide 38 was finally obtained. To investigate its chemical properties, 38 was coupled with primary alcohol 7 using NIS/Lewis acid promoter system (Table 13). At first, coupling of 38 and 7 gave desired product 39 in 86% yield (Table 13, entry 1). However, further glycosylation of 39 with fucosyl thioglycoside 12 gave undesired N-succinimide side product. Then we decided to change the Lewis acid to TfOH as the promoter, most disaccharides 38 were not activated at 60 ^oC, but we got the desired product 39 in 88% yield after raising the temperature to 50 ^oC (Table 13, entries 2 and 3).

According to the experimental results in Table 13, the NIS/TfOH promoter system was employed in further glycosylation with fucosyl thioglycosides 12. According to our retrosynthetic analysis, glycosylation of 39 with 12 should give the Lewis Y tetrasaccharide; however, we obtained the trisaccharide glycosylation product 40 even using 4 equiv of fucosyl thioglycoside and 1.2 equiv of TfOH.

Table 13. Glycosylation studies of donor 38 and acceptor 7

O BnO OBn BnO

OH O O

OBn HO N(Cbz)Bn

STol

HO(CH₂)₆Cl 7, NIS, Lewis acid

DCM, T

O BnO OBn BnO

OH O O

OBn HO N(Cbz)Bn

38 39, R = (CH₂)₆Cl

Entry Lewis acid promoter (equiv.) T (^oC) Yield (%)

1 TMSOTf (0.3) 65 39 (86%)

2 TfOH (0.3) 60 38 (80%)

3 TfOH (0.3) 50 39 (88%)

Owing to the phenomenon of resonance peak broadening for 40, its preliminary identification was evidenced by mass spectroscopy. In addition, the one-pot deprotection by hydrogenolysis reaction was useful for the trisaccharide 40 by using the Pd(OH)2 catalyst (Degussa type) at room temperature instead of 60 ^oC. For further characterizations of the structure, the resulting debenzylated product was acetylated to produce the peracetyl Fuc--(1→3)-Gal--(1→4)-GlcNAc trisaccharide 41 which constitutes part of the H blood group substrate. In this stage, we have synthesized the trisaccharide glycosylation product 40 by stepwise glycosylation. Subsequently, synthesis of 40 from 38 was attempted. Fortunately, we obtained the trisaccharide 40 in 55% yield by one-pot glycosylation reaction (Scheme 24). It was a pity that the 3-OH group in the GlcNAc could not be glycosylated with the fucosyl thioglycoside to give Lewis Y oligosaccharide probably because of the steric hindrance.

O BnO OBn BnO

OH O O

OBn HO N(Cbz)Bn

STol 38

O BnO OBn BnO

O O O

OBn HO N(Cbz)Bn

O(CH₂)₆Cl

O BnOOBn OBn

40 O

AcO OAc AcO

O O O

OAc AcO NHAc

O(CH2)6Cl

O AcOOAc OAc

one-pot glycosylation

one-pot deprotection&

acetylation

HO(CH₂)₆Cl 7

BnOOBn OBnSTol 12

Scmeme 24. Synthesis of trisaccharide 41 via one-pot glycosylation and deprotection strategy

3. Conclusion

In summary, the joined use of N-benzyl oxazolidinoe and N-BnCbz desymmetric amino protection is a versatile strategy for protection of 2-amino sugars. We have used oxazolidinone protected thioglucosamines which have lower anomeric reactivity as acceptors in reactivity-based chemoselective glycosylation. In addition, we have developed the desymmetric N-BnCbz protecting group including its installation, deprotection, and application in oligosaccharides synthesis. Disaccharides such as type 1 LacNAc, type 2 LacNAc, Fuc-a-(1→3)-GlcNAc, and Fuc-a-(1→4)-GlcNAc and trisaccharides H blood group substrate were synthesized based on this strategy.

Moreover, one-pot global deprotection by hydrogenolysis reaction was also developed for both disaccharide and trisaccharide. Further application of this strategy such as Lewis Y tetrasaccharide synthesis is under investigations.

4. Experimental 4.1 General procedures

Chemicals were purchased as reagent grade from commercial venders and used without further purification. All of solvents were dried and distilled by standard techniques unless mentioned.Optical rotations were measured with the JASCO DIP-1000 polarimeter at 30˚C. Flash column chromatography was performed over silica gel 60 (70230 mesh, E. Merck). NMR spectra were recorded with the Brüker console, Varian Unity-300 and Varian Unity-500. Chemical shifts are reported in ppm relative to internal tetramethylsilane (δ = 0.00 ppm) for ¹H and ¹³C resonance signal of CDCl3 (δ = 77.00 ppm) for ¹³C NMR spectra. Coupling constant(s) in hertz (Hz) were derived from ¹H NMR spectra.

4.2 General procedure for glycosylations

Glycosyl donor (8, 9, 10, 11, 12, 27 or 28), glycosyl acceptor (4 or 26), and activated 4 Å MS (100mg/1mL DCM, AW300) in CH2Cl2 were stirred at room temperature under nitrogen for 20 min. The mixture was then cooled in a cooling bath followed by addition of TMSOTf and NIS. After disappearance of acceptor detected by TLC, the mixture was diluted with CH2Cl2, quenched by Et3N, and few droplets of sat. NaHCO3 and excess of Na2S2O3(s) were added, removed from cooling bath, and then stirred at room temperature for 2h. The quenching mixture was then stirred at room temperature for 2h, filtered and finally concentrated. The residue was purified by column chromatography over silica gel to give 13, 14, 15, 16, 17, 30, 31, 32 or 33.

The stoichiometric amounts of substrates and reagents were listed below (Table 13).

Table 14. The amounts of glycosyl donor, glycosyl acceptor, NIS, and TMSOTf used in glycosylation Glycosyl donor

(mg, mmol)

Glycosyl acceptor (mg, mmol)

NIS (mg, mmol)

TMSOTf (uL, mmol, mM)

DCM (mL)

Temp.

(^oC)

Product

8, 160, 0.244 4, 100, 0.204 55, 0.244 9, 0.049, 0.016 3 70 13 9, 159, 0.265 4, 100, 0.204 60, 0.265 10, 0.053, 0.013 4 60 14 10, 173, 0.265 4, 100, 0.204 60, 0.265 10, 0.053, 0.013 4 65 15 11, 175, 0.265 4, 100, 0.204 60, 0.265 10, 0.053, 0.013 4 70 16 12, 165, 0.306 4, 100, 0.204 69, 0.306 11, 0.061, 0.015 4 60 17 11, 734, 1.112 26, 600, 0.856 252, 1.112 31, 0.171, 0.007 24 70 30 28, 780, 1.275 26, 597, 0.850 289, 1.275 31, 0.170, 0.007 25 65 31 29, 198, 0.293 26, 158, 0.225 67, 0.293 8, 0.045, 0.008 6 65 32 12, 486, 0.899 26, 420, 0.599 204, 0.899 22, 0.120, 0.007 17 70 33

4.3 Procedures and experimental data

p-Tolyl N-Benzyl-2-amino-4,6-O-benzylidene-2,3-N,O-carbonyl-2-deoxy-1-thio--

D-glucopyranoside (3):

O STol HO

OH HO

NHTroc

C₆H₅CH(OMe)₂, cat. TsOH CH₃CN, rt 1

O STol NHTroc OO

Ph HO

BnBr, NaH DMF, 0^oCrt

O STol OO

O NBn O

To a solution of compound 1 (2.0 g, 4.36 mmol) and TsOH (67 mg, 0.35 mmol) in CH3CN (15 mL) at room temperature, was added C6H5CH(OMe)2 (0.78 mL, 5.23 mmol). After stirring for 4 h, the mixture was neutralized with NEt3 and then concent- rated under reduced pressure. The residue was crystallized from (EtOAc/hexane) to give compound 2 (2.2 g, 92%) as white solid. Counpound 2 (2.2 g, 4.02 mmol) was dissolved in dry DMF (20 mL) and stirred in an ice bath under nitrogen for 20 min.

Then NaH (241 mg, 6.03 mmol, 60% in mineral oil) was added, followed by addition of benzyl bromide (0.58 mL, 4.82 mmol). After stirring for 30 min, the reaction mixture was warmed to room temperature and stirred for 2h. The reaction was concentrated under reduced pressure and purified by column chromatography over silica gel (EtOAc/CH2Cl2/hexane, 1:1:3) to give 3 (1.57 g, 80%) as white solid. Rf = 0.45 (EtOAc/CH2Cl2/hexane, 1:1:3); []³⁰D -66 (c 1, CHCl3); ¹H NMR (300 MHz, CDCl3) δ: 7.46–7.29 (m, 10H; Ar-H), 7.17–7.07 (m, 4H; Ar-H), 5.56 (s, 1H;

4.75 (d, J= 15.9 Hz, 1H; PhCH2), 4.31–4.24 (m, 2H; H-5, H-6), 3.99 (t, J= 9.3 Hz, 1H; H-4), 3.86 (t, J= 10.3 Hz, 1H; H-6), 3.54–3.45 (m, 2H; H-3, H-2), 2.33 (s, 3H, Ar-CH3); ¹³C NMR (75 MHz, CDCl3) δ: 158.9 (C=O), 139.1, 136.4, 133.2, 129.9, 129.3, 128.7, 128.3, 128.0, 127.9, 127.6, and 126.1 (Ar-C), 101.4 (benzylidene-C), 88.0 (C-1), 78.9 (C-5), 78.4 (C-4), 72.7 (C-3), 68.3 (C-6), 61.5(C-2) , 47.7 (PhCH2), 21.1 (Ar-CH3).

p-Tolyl N-Benzyl-2-amino-6-O-benzyl-2,3-N,O-carbonyl-2-deoxy-1-thio--D- glucopyranoside (4)

O STol HO

O NBn O

OBn

A solution of compound 3 (200 mg, 0.41 mmol), triethylsilane (322 L, 2.05 mmol), and activated 4 Å MS (200 mg, AW300) in CH2Cl2 (2 mL) was stirred at room temperature under nitrogen atmosphere for 20 min. The mixture was then cooled to 20 ^oC in a cooling bath followed by addition of dry trifluoroacetic acid (177L, 2.5 mmol). After 1h, the mixture was diluted with CH2Cl2 (6 mL), and then quenched with Et3N (0.4 mL, 3.3 mmol) at 20 ^oC. MS in the mixture was filtered off and the filtrate was concentrated. The residue was purified by column chromatogram- phy on silica gel (EtOAc/CH2Cl2/hexane, 1:1:8→1:1:3) to give 4 (161 mg, 80%) as white solid. Rf = 0.09 (EtOAc/ CH2Cl2/hexane, 1:1:3); []³⁰D -54 (c 2.38, CHCl3); ¹H NMR (300 MHz, CDCl3) δ: 7.40–7.21 (m, 12H; Ar-H), 7.03–7.01 (d, 2H; Ar-H), 4.73 (s, 1H; PhCH2), 4.69 (d, J= 9.3 Hz, 1H; H-1), 4.57 (d, J= 12.3 Hz, 1H; PhCH2), 4.53 (d, J= 12.0 Hz, 1H; PhCH2), 4.04 (t, J= 10.3 Hz, 1H; H-3), 3.96 (t, J= 9.2 Hz, 1H;

H-4), 3.76 (d, J= 4.5 Hz, 2H; H-6), 3.54–3.48 (m, 1H; H-5), 3.37 (dd, J= 10.7 Hz, J

= 9.6 Hz, 1H; H-2), 2.30 (s, 3H, Ar-CH3); ¹³C NMR (75 MHz, CDCl3) δ: 159.5 (C=O), 138.6, 137.7, 136.3, 132.9, 129.8, 128.6, 128.4, 128.1, 127.74, 127.69, and 127.5 (Ar-C), 86.7 (C-1), 82.5 (C-3), 79.9 (C-5), 73.5 (PhCH2), 69.5 (C-6), 68.5 (C-4), 60.1(C-2) , 47.4 (PhCH2), 21.1 (Ar-CH3); HRMS (ESI) calcd for C28H29NO5S [M+Na]⁺: 514.1664, found: 514.1659.

p-Tolyl N-Benzyl-2-amino-4-acetyl-6-O-benzyl-2,3-N,O-carbonyl-2-deoxy-1-thio-

-D-glucopyranoside (5)

O STol AcO

O NBn O

OBn

To a solution of compound 4 (500 mg, 1.02 mmol) in pyridine (5 mL) at room temperature, was added acetic anhydride (145 μL, 1.53 mmol). After stirring for 2h, the mixture was directly concentrated under reduced pressure, and the residue was purified by column chromatography over silica gel (EtOAc/hexane, 1:7→1:4) to give 5 (516 mg, 95%) as colorless foam. Rf = 0.30 (EtOAc/hexane, 1:2); ¹H NMR (300 MHz, CDCl3) δ: 7.33 (m, 12H; Ar-H), 6.94 (d, J = 7.8 Hz, 2H; Ar-H), 5.20 (dd, J = 10.4 Hz, J = 8.4 Hz, 1H), 4.674.64 (m, 3H; H-1, PhCH2), 4.47 (d, J = 11.7 Hz, 1H), 4.40(d, J = 11.7 Hz, 1H), 4.094.02 (m, 1H), 3.633.51 (m, 3H), 3.44 (dd, J = 11.3 Hz, J = 9.3 Hz, 1H), 2.23 (s, 3H; Ar-CH3), 1.93 (s, 3H; CH3CO);¹³C NMR (75 MHz, CDCl3) δ: 138.7, 137.6, 136.0, 132.9, 129.8, 128.6, 128.3, 128.12, 128.08, 127.7, 127.63, 127.56, 86.7 (C-1), 79.9, 78.7, 73.4, 68.6, 67.8, 60.1, 47.4, 21.0, 20.6.

p-Tolyl N-Benzyl-2-amino-6-O-benzyl-2,3-N,O-carbonyl-2-deoxy-1-thio--D- glucopyranoside (6)

HOO O O NBn

OBn

6 STol

Based on literature stoichiometric amounts of reagents and the same experimental procedure as in the synthesis 4, a mixture of 4 and 6 was obtained, and the ratio was determined by integration of the ¹H NMR spectrum (4:6 = 1:6, 65%).

We separated the -glycoside 6 and obtained its characterization data. Rf = 0.15 (EtOAc/CH2Cl2/hexane, 1:1:3); []³⁰D 168 (c 0.24, CHCl3); ¹H NMR (300 MHz, CDCl3) δ: 7.36–7.23 (m, 12H; Ar-H), 7.09 (d, 2H; Ar-H), 5.32 (d, J= 4.5 Hz, 1H;

H-1), 4.78 (d, J= 14.7 Hz, 1H; PhCH2), 4.59 (d, J= 12.0 Hz, 1H; PhCH2), 4.49 (d, J

= 12.0 Hz, 1H; PhCH2), 4.36 (dd, J= 11.9 Hz, J= 9.8 Hz, 1H; H-3), 4.19–4.11 (m, 2H; H-5, PhCH2), 4.00 (td, J= 9.3 Hz, J= 3.0 Hz, 1H; H-4), 3.78 (dd, J= 10.5 Hz, J

= 4.5 Hz, 1H; H-6), 3.71 (dd, J= 10.5 Hz, J= 4.5 Hz, 1H; H-6), 3.49 (dd, J= 12 Hz, J= 4.5 Hz, 1H; H-2), 2.99 (d, 1H, J= 3.3 Hz, 4-OH), 2.34 (s, 3H, Ar-CH3); ¹³C NMR (75 MHz, CDCl3) δ: 158.6 (C=O), 138.3, 137.5, 134.4, 132.4, 129.94, 129.0, 128.9, 128.5, 128.4, 127.9, and 127.8 (Ar-C), 85.2 (C-1), 78.4 (C-3), 73.6 (PhCH2), 72.9 (C-5), 69.4 (C-4), 68.7 (C-6), 59.2(C-2) , 47.4 (PhCH2), 21.1 (Ar-CH3).

p-Tolyl 2,3,4-Tri-O-benzyl-6-O-levulinoyl--D-galactopyranosyl-(1→4)-N-benzyl- 2-amino-6-O-benzyl-2,3-N,O-carbonyl-2-deoxy-1-thio--D-glucopyranoside (13)

O STol O

O NBn O

OBn O

BnO OLev BnO

BnO

Compound 13 was prepared from 8 and 4, and the stoichiometric amounts were referred to Table 13. The residue was purified by column chromatography over silica gel (EtOAc/CH2Cl2/hexane, 1:1:7→1:1:3) to give 13 (146 mg, 70%) as amorphous white solid. Rf = 0.21 (EtOAc/CH2Cl2/hexane, 1:1:3); []³⁰D +9 (c 2.67, CHCl3); ¹H NMR (300 MHz, CDCl3) δ: 7.42–7.22 (m, 27H, Ar-H), 6.99 (d, J = 11.1 Hz, 2H;

Ar-H), 5.44 (d, J = 3.6 Hz, 1H; H-1), 4.94 (d, J= 11.1 Hz, 1H; PhCH2), 4.87–4.64 (m, 7H), 4.62–4.55 (m, 2H), 4.47 (d, J= 12.0 Hz, 1H; PhCH2), 4.21–4.06 (m, 4H), 3.94 (dd, J= 11.1 Hz J= 5.7 Hz, 1H), 3.763.65 (m, 6H), 3.45 (t, J= 10.1 Hz, 1H; H-2), 2.672.62 (m, 2H; CH2), 2.452.40 (m, 2H; CH2), 2.29 (s, 3H; Ar-CH3), 2.12 (s, 3H;

CH3); ¹³C NMR (75 MHz, CDCl3) δ: 206.2 (C=O), 172.1 (C=O), 158.7 (C=O), 138.6, 138.5, 138.1, 138.0, 136.2, 132.8, 129.8, 128.6, 128.32, 128.26, 128.22, 128.14, 128.06, 127.7, 127.6, 127.5, and 127.3 (Ar-C), 96.3 (C’-1), 86.4 (C-1), 82.7, 79.1, 78.2, 75.8, 74.4 (PhCH2), 74.1, 73.34 (PhCH2), 73.29 (PhCH2), 73.1 (PhCH2), 71.0, 69.2, 69.0, 63.4, 60.0 (C-2), 47.4 (PhCH2), 37.7 (CH2), 29.8 (CH3), 27.6 (CH2), 21.1 (Ar-CH3). HRMS (ESI) calcd for C60H63NO12S [M+Na]⁺: 1044.3969, found:

1044.3962.

p-Tolyl 3,4,6-Tri-O-benzyl-2-O-levulinoyl--D-galactopyranosyl-(1→4)-N-benzyl- 2-amino-6-O-benzyl-2,3-N,O-carbonyl-2-deoxy-1-thio--D-glucopyranoside (15)

O STol O

O NBn O O OBn BnO OBn

BnO

OLev 15

Compound 15 was prepared from 10 and 4, and the stoichiometric amounts were

referred to Table 13. The residue was purified by column chromatography over silica gel (EtOAc/CH2Cl2/hexane, 1:1:8→1:1:3) to give 15 (135 mg, 65%) as amorphous white solid. Rf = 0.19 (EtOAc/CH2Cl2/hexane, 1:1:3); []³⁰D -21 (c 1, CHCl3); ¹H NMR (500 MHz, CDCl3) δ: 7.42–7.26 (m, 27H; Ar-H), 7.05–7.02 (m, 2H, Ar-H), 5.37 (t, J= 9.0 Hz, 1H), 4.93 (dd, J = 11.5 Hz, J = 3.5 Hz, 1H), 4.794.74 (m, 2H), 4.694.60 (m, 4H), 4.574.46 (m, 5H), 4.21 (td, J = 10.5 Hz, J = 4.5 Hz, 1H), 4.104.06 (m, 1H), 4.003.97 (m, 1H), 3.823.71 (m, 4H), 3.663.63 (m, 1H), 3.613.59 (m, 1H), 3.49 (dd, J = 10.3 Hz, J = 2.75 Hz, 1H), 3.423.37 (m, 1H), 2.682.62 (m, 2H; CH2), 2.532.46 (m, 2H; CH2), 2.32 (s, 3H; Ar-CH3), 2.11 (s, 3H;

CH3); ¹³C NMR (125 MHz, CDCl3) δ: 206.1 (C=O), 171.2 (C=O), 158.9 (C=O), 138.4, 138.2, 138.1, 137.9, 137.7, 136.3, 132.8, 129.7, 128.4, 128.24, 128.23, 128.14, 128.10, 128.05, 128.00, 127.95, 127.7, 127.60, 127.56, 127.48, 127.44, 127.37, and 127.33 (Ar-C), 100.3 (C’-1), 86.2 (C-1), 81.0, 80.0, 79.6, 74.31 (PhCH2), 74.28, 73.5, 73.4 (PhCH2), 73.3 (PhCH2), 72.3, 71.8 (PhCH2), 71.6, 68.2, 68.1, 60.2, 47.3 (PhCH2), 37.5 (CH2), 29.6 (CH2), 27.7 (CH2), 21.0 (Ar-CH3); HRMS (ESI) calcd for C60H63NO12S [M+Na]⁺: 1044.3969, found: 1044.4080.

p-Tolyl 2-O-Benzoyl-3,4,6-tri-O-benzyl--D-galactopyranosyl-(1→4)-N-benzyl-2- amino-6-O-benzyl-2,3-N,O-carbonyl-2-deoxy-1-thio--D-glucopyranoside (16)

O STol O

O NBn O O OBn BnO OBn

BnO

OBz 16

Compound 16 was prepared from 11 and 4, and the stoichiometric amounts were

referred to Table 13. The residue was purified by column chromatography over silica gel (EtOAc/CH2Cl2/hexane, 1:1:7→1:1:4) to give 16 (167 mg, 80%) as amorphous white solid. Rf = 0.20 (EtOAc/CH2Cl2/hexane, 1:1:4); []³⁰D -12 (c 2.19, CHCl3); ¹H NMR (300 MHz, CDCl

), 47.3

3) δ: 7.97 (d, J = 8.4 Hz, 2H; Ar-H), 6.91 (t, J = 8.1 Hz, 1H;

Ar-H), 7.417.07 (m, 29H; Ar-H), 6.91 (d, J = 8.1 Hz, 2H; Ar-H), 5.76 (dd, J = 10.1 Hz, J = 8.0 Hz, 1H), 4.94 (d, J = 11.4 Hz, 1H), 4.694.52 (m, 7H), 4.474.35 (m, 3H), 4.183.94 (m, 4H), 3.753.66 (m, 3H), 3.463.39 (m, 3H), 3.40 (dd, J = 10.2 Hz, J = 2.7 Hz, 1H), 2.22 (s, 3H, Ar-CH3); ¹³C NMR (75 MHz, CDCl3) δ: 165.6 (C=O), 158.9 (C=O), 138.4, 138.2, 138.0, 137.9, 137.6, 137.4, 136.2, 128.5, 128.3, 128.2, 128.18, 128.13, 128.06, 128.01, 127.8, 127.6, 127.3 (Ar-C), 100.8 (C’-1), 86.2 (C-1 81.3, 79.4, 79.0, 74.7, 74.4, 73.6, 73.5, 72.7, 72.0, 71.9, 71.3, 68.1, 67.7, 60.0,

(PhCH2), 21.0 (Ar-CH3); HRMS (ESI) calcd for C62H61NO11S [M+Na]⁺: 1050.3863, found: 1050.3860.

p-Tolyl 2,3,4-Tri-O-benzyl--L-fucopyranosyl-(1→4)-N-benzyl-2-amino-6-O- benzyl-2,3-N,O-carbonyl-2-deoxy-1-thio-D-glucopyranoside (17)

O BnO OBn

OBn O O STol

O NBn O

OBn

17 (:= 1:3.5)

Compound 17 was prepared from 12 and 4, and the stoichiometric amounts were referred to Table 13. The residue was purified by column chromatography over silica gel (EtOAc/CH2Cl2/hexane, 1:1:9→1:1:5) to give 17 (157 mg, 85%) as an

Ar-CH3 1H resonance signals at ca. 2.3 ppm of the reaction mixture. Rf = 0.28 (EtOAc/ CH2Cl2/hexane, 1:1:5); HRMS (ESI) calcd for C55H57NO9S [M+Na]⁺: 930.3652, found: 930.3723.

p-Tolyl N-Benzyl-2-amino-4,6-di-O-benzyl-2,3-N,O-carbonyl-2-deoxy-1-thio--D- glucopyranoside (19)

O STol BnO

O NBn O

OBn

Counpound 1 (600 mg, 1.31 mmol) was dissolved in dry DMF (10 mL) and stirred at 15 ^oC under nitrogen for 20 min. Then NaH (314 mg, 7.84 mmol, 60% in mineral oil) was added, followed by addition of benzyl bromide (0.7 mL, 5.88 mmol).

After stirring in a cooling bath for 30 min, the reaction mixture was warmed to room temperature and stirred for 2h. The reaction was quenched with crushed ice, stirred at room tempeture for 10 min, and the whole was extracted with EtOAc (30 mL × 3).

The organic layer was washed with brine (30 mL), dried over MgSO4, filtered, and finally concentrated. The residue was purified by column chromatography over silica gel (EtOAc/hexane, 1:3) and then crystallized from (EtOAc/hexane) to give 19 (608 mg, 80%) as white amorphous solid. Rf = 0.43 (EtOAc/hexane, 1:3); []³⁰D -32 (c 0.87, CHCl3); ¹H NMR (300 MHz, CDCl3) δ: 7.43–7.23 (m, 17H, Ar-H), 7.00 (d, J= 8.1 Hz, 2H; Ar-H), 4.88 (d, J= 11.1 Hz, 1H; PhCH2), 4.86 (s, 2H; PhCH2), 4.69 (d, J

= 9.3 Hz, 1H; H-1), 4.56 (d, J = 12.0 Hz, 1H; PhCH2), 4.54 (d, J = 11.4 Hz, 1H;

PhCH2), 4.48 (d, J= 12.0 Hz, 1H; PhCH2), 4.16 (dd, J= 11.1 Hz, J= 9.9 Hz, 1H;

H-3), 3.86 (dd, J= 9.6 Hz, J=8.7 Hz, 1H; H-4), 3.75 (dd, J= 10.8 Hz, J= 2.1 Hz, 1H;

H-6), 3.67 (dd, J= 10.8 Hz, J= 4.5 Hz, 1H; H-6), 3.58–3.53 (m, 1H; H-5), 3.44 (dd, J

= 11.1 Hz, J= 9.6 Hz, 1H; H-2), 2.29 (s, 3H; Ar-CH3); ¹³C NMR (75 MHz, CDCl3) δ:

159.2 (C=O), 138.6, 138.0, 137.2, 136.3, 128.6, 128.4, 128.35, 128.29, 128.11, 127.96, 127.89, 127.81, 127.7, 127.6 and 127.5 (Ar-C), 86.6 (C-1), 83.4 (C-3), 79.8 (C-5), 73.6 (C-4), 73.3 and 73.1 (PhCH2), 68.4 (C-6), 60.2 (C-2), 47.4 (PhCH2), 21.1 (Ar-CH3); HRMS (ESI) calcd for C28H29NO5S [M+Na]⁺: 514.1664, found: 514.1659.

p-Tolyl N-Benzyl-2-amino-4,6-di-O-benzyl-2-deoxy-1-thio--D-glucopyranoside (20)

O STol BnO

HO NHBn OBn

To a solution of compound 19 (190 mg, 0.33 mmol) in DMSO (5 mL) at room temperature, was added t-BuOK (183 mg, 1.64 mmol). After stirring for l h, the reaction mixture was diluted with EtOAC, and then washed with water. The aqueous layer was washed with EtOAc three times. The combined organic phase was dried over MgSO4, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography over silica gel (EtOAc/hexane, 1:3) to give 20 (136 mg, 75%) as yellow oil. Rf = 0.18 (EtOAc/hexane, 1:3); []³⁰D -9 (c 2.83, CHCl3); ¹H NMR (300 MHz, CDCl3) δ: 7.47 (d, J= 8.1 Hz, 2H; Ar-H), 7.33–7.20 (m, 15H; Ar-H), 7.01 (d, J= 8.1 Hz, 2H; Ar-H), 4.86 (d, J= 11.1 Hz, 1H; PhCH2), 4.62 (d, J = 10.2 Hz, 1H; H-1), 4.59 (d, J= 11.1 Hz, 1H; PhCH2), 4.58 (d, J= 11.1 Hz, 1H;

PhCH2), 4.51 (d, J= 12.0 Hz, 1H; PhCH2), 3.94 (d, J= 12.3 Hz, 1H; PhCH2), 3.84 (d, J= 12.3 Hz, 1H; PhCH2), 3.81–3.62 (m, 3H; H-3, H-6), 3.52–3.43 (m, 2H; H-4, H-5), 2.63 (t, J= 9.9 Hz, 1H; H-2), 2.28 (s, 3H, Ar-CH3); ¹³C NMR (75 MHz, CDCl3) δ:

140.0, 138.3, 137.6, 132.2, 129.6, 129.4, 128.4, 128.3, 128.19, 128.18, 127.8, 127.6,

127.5, 127.4, and 127.1 (Ar-C), 87.3 (C-1), 78.8 (C-4), 77.9 (C-5), 76.0 (C-3), 74.2 and 73.2 (PhCH2), 69.2 (C-6), 61.7 (C-2), 49.7 (PhCH2), 21.0 (Ar-CH3); HRMS (ESI) calcd for C34H37NO4S [M+H]⁺: 556.2522, found: 556.2516.

p-Tolyl N-Benzyl-N-tert-butoxycarbonyl-2-amino-4,6-di-O-benzyl-2-deoxy-1-thio-

-D-glucopyranoside (22)

O STol BnO

N(Boc)Bn HO

OBn

To a solution of compound 20 (340 mg, 0.61 mmol) and NaHCO3 (410 mg, 4.88 mmol) in non-dried MeOH (6 mL) at room temperature, was added (Boc)2O chloroformate (0.26 mL, 1.22 mmol). After stirring for 2h, MeOH was removed under reduced pressure. The residue was diluted with CH2Cl2 (5 mL), poured into a two-layer mixture of CH2Cl2 (10 mL) and brine (10 mL), and the whole was extracted with CH2Cl2 (20 mL × 3). The combined organic phase was separated, dried over MgSO4, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography over silica gel (EtOAc/CH2Cl2/ hexane, 1:1:5) to give 22 (304 mg, 76%) as yellow oil. Rf = 0.49 (EtOAc/CH2Cl2/ hexane, 1:1:3); HRMS (ESI) calcd for C39H45NO6S [M+Na]⁺: 678.2865, found: 678.2860.

Standard ¹H and ¹³C NMR spectra were obscured by peak broadening.

N-Benzyl-2-amino-3-O-acetyl-4,6-di-O-benzyl-1,2-cis-O,N-carbonyl-2-deoxy-D- glucopyranoside (24)

BnO O

OBn AcO

BnN O O 24

Rf = 0.47 (EtOAc/CH2Cl2/ hexane, 2:2:3); ¹H NMR (300 MHz, CDCl3) δ: 7.30–7.15

3 3

30 31 7

-Tolyl N-Benzyl-N-benzyloxycarbonyl-2-amino-4,6-di-O-benzyl-2-deoxy-1-thio- (m, 15H; Ar-H), 5.76 (d, J = 7.2 Hz, 1H; H-1), 5.24–5.23 (m, 1H), 4.88 (d, J = 15.3 Hz, 1H), 4.63 (d, J = 11.7 Hz, 1H), 4.43 (dd, J = 11.7 Hz, J = 4.5 Hz, 2H), 4.27 (d, J

= 11.7 Hz, 1H), 3.89 (d, J = 15.3 Hz 1H), 3.77–3.72 (m, 1H), 3.66 (d, J = 8.4 Hz, 1H), 3.61–3.56 (m, 1H) 3.52 (dd, J = 15.6 Hz, J = 2.4 Hz, 1H), 3.38 (dd, J = 11.0 Hz, J = 3.6 Hz, 1H), 1.92 (s, 3H; CH CO); ¹³C NMR (75 MHz, CDCl ) δ: 169.6, 156.9, 137.7, 137.1, 134.5, 129.0, 128.50, 128.46, 128.29, 128.27, 128.19, 127.8, 127.7, 93.7 (C-1), 73.3, 72.9, 72.0, 69.6, 68.7, 65.9, 52.7, 46.0, 20.8 (CH CO); HRMS (ESI) calcd for C H NO [M+H]⁺: 518.2179, found: 518.2180.

-D-glucopyranoside (25)

O STol BnO

N(Cbz)Bn HO

OBn

To a solution of compound 20 (870 mg, 1.57 mmol) and NaHCO3 (1.32g, 15.68 mmol) in non-dried MeOH (10 mL) at ro

2 2

4 centr

om temperature, was added benzyl chloroformate (0.8 mL, 2.36 mmol, 50 wt% solution in toluene). After stirring for 2h, MeOH was removed under reduced pressure. The residue was diluted with CH Cl (10 mL), poured into a two-layer mixture of CH Cl (20 mL) and brine (20 mL), and the whole was extracted with CH Cl (40 mL × 3). The combined organic phase was separated, dried over MgSO , filtered, and con ated under reduced pressure. The

residue was purified by column chromatography over silica gel (EtOAc/CH2Cl2/ hexane, 1:1:4) to give 25 (886 mg, 82%) as yellow oil. Rf = 0.31 (EtOAc/CH2Cl2/ hexane, 1:1:4); []³⁰D -6 (c 4, CHCl3); HRMS (ESI) calcd for C42H43NO6S [M+H]⁺: 690.2889, found: 690.2894. Standard ¹H and ¹³C NMR spectra were obscured by peak broadening.

6-Chlorohexyl N-Benzyl-N-benzyloxycarbonyl-2-amino-4,6-di-O-benzyl-2-deoxy-

-D-glucopyranoside (26)

O OR BnO

N(Cbz)Bn HO

OBn

26, R = (CH₂)₆Cl

Compound 25 (1.60 g, 2.32 mmol), 6-chlorohexanol 7 (0.46 mL, 3.48 mmol), and activated 4 Å MS (6.5 g, 100mg/1mL CH2Cl2, AW300) in CH2Cl2 (65 mL) were stirred at room temperature under nitrogen for 20 min. The mixture was then cooled in a cooling bath at 65 ^oC followed by addition of TMSOTf (84 L, 7 mM) and NIS (526 mg, 2.32 mmol). After disappearance of acceptor detected by TLC, the mixture was diluted with CH2Cl2 (65 mL), quenched by Et3N, and few droplets of sat.

NaHCO3 and pieces of Na2S2O3(s) were added. The quenching mixture was then stirred at room temperature for 2h, filtered and finally concentrated. The residue was purified by column chromatography over silica gel (EtOAc/CH2Cl2/hexane, 1:1:8→1:1:3) to give 26 (1.43 g, 88%) as yellow oil. Rf = 0.42 (EtOAc/CH2Cl2/ hexane, 1:1:3); []³⁰D -12 (c 2.33, CHCl3); ¹H NMR (500 MHz, (CD3)2SO, 100^oC) δ:

7.44–7.21 (m, 20H; Ar-H), 5.21–5.10 (m, 2H), 4.93 (d, J= 11.5 Hz, 1H), 4.66–4.45 (m, 6H), 3.73 (d, J= 10.0 Hz, 1H), 3.68–3.55 (m, 5H), 3.52–3.36 (m, 4H), 1.77–1.70 (m, 2H), 1.49–1.36 (m, 4H), 1.34–1.25 (m, 2H); ¹³C NMR (125 MHz, (CD3)2SO,

100^oC) δ: 139.4, 139.0, 128.5, 128.43, 128.36, 128.13, 128.07, 127.95, 127.92, 127.7, 127.59, 127.56, 126.88, 100.0, 80.1, 74.8, 73.9, 73.0, 70.0, 68.7, 66.7, 45.5, 32.5, 29.3, 26.4, 25.1; HRMS (ESI) calcd for C41H48ClNO7 [M+Na]⁺: 724.3017, found:

724.3012. Standard ¹H and ¹³C NMR spectra were obscured by peak broadening in CDCl3, and the peaks became clear at 100^oC in deuterated DMSO solvent based on the VT–NMR experiments.

6-Chlorohexyl N-Benzyl-2-amino-4,6-di-O-benzyl-2-deoxy--D-glucopyranoside (27)

O OR BnO

HO NHBn OBn

27, R = (CH₂)₆Cl

To a solution of compound 26 (100 mg, 0.14 mmol), triethylsilane (90 L, 0.56 mmol), and Et3N (18 L, 0.14 mmol) in CH2Cl2 (1 mL) at room temperature, was added PdCl2 (31 mg, 0.17 mmol). After stirring for 1h, the reaction mixture was diluted with ether (2 mL), filtered, poured into a two-layer mixture of ether (5 mL) and sat. NaHCO3 (5 mL), and the resulting mixture was extracted with ether (5 mL × 3). The combined organic phase was dried over MgSO4, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography over silica gel (EtOAc/CH2Cl2/hexane, 1:1:3→1:1:1) to give 27 (37 mg, 45%) as yellow oil. Rf = 0.38 (EtOAc/CH2Cl2/hexane,1:1:3); []³⁰D +2 (c 0.18, CHCl3); ¹H NMR (300 MHz, CDCl3) δ: 7.40–7.20 (m, 15H; Ar-H), 4.79 (d, J= 11.1 Hz, 1H; PhCH2), 4.63 (d, J= 12.3 Hz, 1H; PhCH2), 4.58 (d, J= 11.1 Hz, 1H; PhCH2), 4.55 (d, J= 12.0 Hz, 1H; PhCH2), 4.31 (d, J = 8.1 Hz, 1H; H-1), 4.09 (d, J= 12.9 Hz, 1H; PhCH2), 4.00–3.92 (m, 1H; O-CH ), 3.87 (d, J= 12.9 Hz, 1H; PhCH ), 3.78–3.66 (m, 2H;

H-6), 3.58– 3.44 (m, 6H, H-3, H-4, H-5; O-CH2, CH2Cl), 2.58 (t, J= 8.7 Hz, 1 H;

H-2), 1.80–1.40 (m, 4H; CH2), 1.54–1.35 (m, 4H; CH2); ¹³C NMR (75 MHz, CDCl3) δ: 140.0, 138.3, 138.2, 128.4, 128.3, 128.2, 127.9, 127.8, 127.6, and 127.0 (Ar-C), 104.0 (C-1), 78.4 (C-4), 75.4 (C-5), 74.9 (C-3), 74.4 and 73.5 (PhCH2), 69.5 (C-6), 69.1 (O-CH2), 62.7 (C-2), 51.7 (PhCH2), 45.0 (CH2Cl), 32.5, 29.6, 26.6, and 25.5 (CH2); HRMS (ESI) calcd for C33H42ClNO5 [M+H]⁺: 568.2830, found: 568.2824.

6-Chlorohexyl 2-Benzoyl-3,4,6-tri-O-benzyl--D-galactopyranosyl-(1→3)-N- benzyl-N-benzyloxycarbonyl-2-amino-4,6-di-O-benzyl-2-deoxy--D -glucopyrano-side (30)

O OBn

BnO OR

N(Cbz)Bn O O

BnO OBn

BnO OBz

30, R = (CH₂)₆Cl

Compound 30 was prepared from 11 and 26, and the stoichiometric amounts were referred to Table 13. The residue was purified by column chromatography over silica gel (EtOAc/CH2Cl2/hexane, 1:1:7→1:1:5) to give 30 (847 mg, 80%) as yellow oil. Rf = 0.31 (EtOAc/CH2Cl2/hexane, 1:1:5); []³⁰D +20 (c 2.38, CHCl3); HRMS (ESI) calcd for C75H80ClNO13 [M+Na]⁺: 1260.5216, found: 1260.5215. Standard ¹H and ¹³C NMR spectra were obscured by peak broadening at room temperature.

6-Chlorohexyl 3-Allyl-2-benzoyl-4,6-di-O-benzyl--D-galactopyranosyl-(1→3)- N-benzyl-N-benzyloxycarbonyl-2-amino-4,6-di-O-benzyl-2-deoxy--D-glucopyra noside (31)

O OBn

BnO OR

N(Cbz)Bn O O

BnO OBn

AllO OBz

31, R = (CH₂)₆Cl

Compound 31 was prepared from 28 and 26, and the stoichiometric amounts were referred to Table 13. The residue was purified by column chromatography over silica gel (EtOAc/CH2Cl2/hexane, 1:1:8→1:1:6) to give 31 (738 mg, 73%) as yellow oil. Rf = 0.41 (EtOAc/CH2Cl2/hexane, 1:1:5); []³⁰D 10 (c 1.29, CHCl3); HRMS (ESI) calcd for C71H78ClNO13 [M+Na]⁺: 1210.5059, found: 1210.5054. Standard ¹H and

13C NMR spectra were obscured by peak broadening.

6-Chlorohexyl 2-O-Benzoyl-4,6-di-O-benzyl-3-paramethoxybenzyl--D-galactop- yranosyl-(1→3)-N-benzyl-N-benzyloxycarbonyl-2-amino-4,6-di-O-benzyl-2-deox y--D-glucopyranoside (32)

O OBn

BnO OR

N(Cbz)Bn O O

BnO OBn

PMBO OBz

32, R = (CH2)6Cl

Compound 32 was prepared from 29 and 26, and the stoichiometric amounts were referred to Table 13. The residue was purified by column chromatography over silica gel (EtOAc/CH2Cl2/hexane, 1:1:8) to give 32 (197 mg, 70%) as yellow oil. Rf = 0.23 (EtOAc/CH2Cl2/hexane, 1:1:5). Standard ¹H and ¹³C NMR spectra were obscured by peak broadening.

6-Chlorohexyl 2,3,4-Tri-O-benzyl--L-fucopyranosyl-(1→3)-N-benzyl-N-benzyl- oxycarbonyl-2-amino-4,6-di-O-benzyl-2-deoxy--D-glucopyranoside (33)

O OBn

BnO OR

N(Cbz)Bn O

O BnOOBn

OBn

33, R = (CH2)6Cl

Compound 33 was prepared from 12 and 26, and the stoichiometric amounts were referred to Table 13. The residue was purified by column chromatography over silica gel (EtOAc/CH2Cl2/hexane, 1:1:10→1:1:8) to give 33 (623 mg, 93%) as yellow oil. Rf = 0.44 (EtOAc/CH2Cl2/hexane, 1:1:5); []³⁰D -43 (c 0.98, CHCl3); HRMS (ESI) calcd for C68H76ClNO11 [M+Na]⁺: 1140.5005, found: 1140.5008. Standard ¹H and ¹³C NMR spectra were obscured by peak broadening.

6-Chlorohexyl 2-acetamido-3,4,6-tri-O-acetyl--D-glucopyranoside (34)

AcO O

OAc AcO NHAc

OR 34, R = (CH₂)₆Cl

A solution of compound 26 (200 mg, 0.29 mmol) and 20 % Pd(OH)2/C (100 mg) in EtOAc/H2O/AcOH (6 mL, 2:1:4) was stirred at 60 ^oC under hydrogen at 1 atm overnight. The catalyst was filtered off through celite and the filtrate was concentrated.

To a solution of the reaction crude in pyridine (4 mL) at room temperature was added acetic anhydride (2 mL). After stirring for 4h, the mixture was directly concentrated under reduced pressure, and the residue was purified by column chromatography over

silica gel (EtOAc/CH2Cl2, 1:8→1:4) to give 34 (92 mg, 70%) as white solid. Rf = 0.19 (EtOAc/CH2Cl2, 1:4); []³⁰D -11 (c 0.95, CHCl3); ¹H NMR (300 MHz, CDCl3) δ: 6.11 (d, J = 8.7 Hz, 1H), 5.31 (dd, J = 10.5 Hz, J = 9.6 Hz, 1H), 5.06 (t, J = 9.6 Hz, 1H), 4.70 (d, J = 8.4 Hz, 1H; H-1), 4.27 (dd, J = 12.3 Hz, J = 4.8 Hz, 1H), 4.14 (dd, J

= 12.0 Hz, J = 2.4 Hz, 1H), 3.91–3.81 (m, 2H), 3.76–3.70 (m, 1H), 3.54 (t, 6.6 Hz, 3H), 2.09 (s, 3H, CH3CO), 2.04 (s, 3H, CH3CO), 2.03 (s, 3H, CH3CO), 1.95 (s, 3H, CH3CO), 1.81–1.72 (m, 2H, CH2), 1.64–1.54 (m, 2H, CH2), 1.47–1.32 (m, 4H, CH2);

13C NMR (75 MHz, CDCl3) δ: 170.7 (C=O), 170.6 (C=O), 170.2 (C=O), 169.3 (C=O), 100.6 (C-1), 72.3, 71.5, 69.4, 68.7, 62.1, 54.5, 44.9 (CH2Cl), 32.3 (CH2), 29.1 (CH2), 26.3 (CH2), 25.0 (CH2), 23.1 (CH3CO), 20.63 (CH3CO), 20.58 (CH3CO), 20.50 (CH3CO); LRMS (ESI) calcd for C20H32ClNO9 [M+H]⁺: 466.18, found: 466.15.

6-Chlorohexyl 3,4,6-Tri-O-acetyl-2-O-benzoyl--D-galactopyranosyl-(1→3)-2- acetamido-4,6-di-O-acetyl--D-glucopyranoside (35)

O OAc

AcO OR

O NHAc OAcO

AcO

AcO OBz

35, R = (CH₂)₆Cl

A solution of compound 30 (175 mg, 0.14 mmol) and 20 % Pd(OH)2/C (100 mg) in EtOAc/H2O/AcOH (6 mL, 2:1:4) was stirred at 60 ^oC under hydrogen at 1 atm overnight. The catalyst was filtered off through celite and the filtrate was concentrated.

To a solution of the reaction crude in pyridine (4 mL) at room temperature, was added acetic anhydride (2 mL). After stirring for 4h, the mixture was directly concentrated under reduced pressure, and the residue was purified by column chromatography over silica gel (CH2Cl2/MeOH, 80:1→40:1) to give 35 (67 mg, 58%) as colorless foam. Rf

= 0.37 (EtOAc/CH2Cl2, 1:1); []³⁰D +2 (c 0.52, CHCl3); ¹H NMR (300 MHz, CDCl3) δ: 8.00 (d, 2H; Ar-H), 7.64 (t, 1H; Ar-H), 7.50 (t, 2H; Ar-H), 5.40–5.32 (m, 3H), 5.25–5.20 (m, 1H), 5.05 (d, J = 8.1 Hz, 1H; H’-1), 4.95 (t, 1H), 4.69–4.63 (m, 2H), 4.30–4.00 (m, 4H), 3.99 (t, 1H), 3.79–3.73 (m, 1H), 3.69–3.60 (m, 1H), 3.50 (t, 2H), 3.44–3.38 (m, 1H), 2.85–2.70 (m, 1H), 2.20–1.85 (m, 18H; CH3CO), 1.85–1.70 (m, 2H; CH2), 1.60–1.10 (m, 6H; CH2); ¹³C NMR (75 MHz, CDCl3) δ: 170.9, 170.7, 170.3, 170.2, 170.0, 169.3 and 164.6 (C=O), 133.7, 129.5, 129.2, 128.7 (Ar-C), 100.9 (C’-1), 98.3 (C-1), 71.6, 70.6, 69.9, 69.8, 69.0, 66.9, 62.4, 61.0, 58.9, 44.8 (CH2), 32.3 (CH2), 29.1 (CH2), 26.4 (CH2), 25.0 (CH2), 23.4 (CH3CO), 20.71 (CH3CO), 20.66 (CH3CO), 20.6 (CH3CO), 20.4 (CH3CO); HRMS (ESI) calcd for C37H50ClNO17 [M+Na]⁺: 838.2665, found: 838.2659.

6-Chlorohexyl 2,3,4-Tri-O-acetyl--L-fucopyranosyl-(1→3)-2-acetamido-4,6-di- O-acetyl--D-glucopyranoside (36)

O OAc

AcO OR

NHAc O

O AcOOAc

OAc 36, R = (CH2)6Cl

A solution of compound 33 (180 mg, 0.16 mmol) and 20 % Pd(OH)2/C (100 mg) in EtOAc/H2O/AcOH (10 mL, 5:1:4), was stirred at 60 ^oC under hydrogen at 1 atm overnight. The catalyst was filtered off through celite and the filtrate was concentrated.

= 0.15 (EtOAc/CH2Cl2, 1:4); []³⁰D -36 (c 0.61, CHCl3); ¹H NMR (500 MHz, CDCl3) δ: 5.80 (d, J = 7.0 Hz, 1H), 5.31 (dd, J = 11.0 Hz, J = 3.0 Hz, 1H), 5.265.24 (m, 2H), 5.09 (dd, J = 11.0 Hz, J = 3.5 Hz, 1H), 4.994.92 (m, 2H), 4.42 (t, J = 9.5 Hz, 1H), 4.204.13 (m, 2H), 4.08 (dd, J = 12.0 Hz, J = 2.5 Hz, 1H), 3.873.82 (m, 1H), 3.643.58 (m, 1H), 3.54 (t, J = 6.8 Hz, 2H), 3.513.46 (m, 1H), 3.2 (m, 1H) 2.15 (s, 3H) 2.11 (s, 3H) 2.08 (s, 3H), 2.07 (s, 3H), 1.98 (s, 6H), 1.801.74 (m, 4H), 1.621.74 (m, 2H), 1.481.42 (m, 2H); 1.08 (d, J = 6.5 Hz, 3H);¹³C NMR (125 MHz, CDCl3) δ: 170.7, 170.6, 170.5, 169.9 and 169.7 (C=O), 99.0 (C-1), 96.8 (C’-1), 76.2, 71.8, 71.2, 71.0, 69.7 (PhCH2), 68.7, 67.3, 65.5, 62.6 (CH2), 58.0, 45.0 (CH2), 32.4 (CH2), 29.2 (CH2), 26.5 (CH2), 25.2 (CH2), 23.6 (CH3CO), 21.0 (CH3CO), 20.9 (CH3CO), 20.8 (CH3CO), 20.7 (CH3CO), 20.6 (CH3CO), 15.5 (CH3CO); HRMS (ESI) calcd for C30H46ClNO15 [M+Na]⁺: 718.2454, found: 718.2448.

p-Tolyl 3,4,6-Tri-O-benzyl--D-galactopyranosyl-(1→4)-N-benzyl-2-amino-6-O- benzyl-2-deoxy-1-thio--D-glucopyranoside (37)

O STol O

HO NHBn O OBn BnO OBn

BnO

OH 37

A solution of compound 16 (300 mg, 0.29 mmol) in 1M NaOH (9 mL) and 1,4-dioxane (9 mL) was stirred at 80 ^oC for 12h. The mixture was cooled to room temperature, diluted with EtOAc, and then washed with water. The aqueous layer was washed with EtOAc three times. The combined organic phase was dried over MgSO4, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography over silica gel (CH Cl /MeOH, 50:1) to give 37 (220 mg, 84%) as

yellow oil. Rf = 0.22 (CH2Cl2/MeOH, 50:1); []³⁰D -25 (c 2.42, CHCl3); ¹H NMR (300 MHz, CDCl3) δ: 7.43–7.16 (m, 27 H; Ar-H), 7.01 (d, J = 8.1 Hz, 2H; Ar-H), 4.86 (d, J= 11.7 Hz, 1H), 4.68 (s, 2H), 4.59–4.50 (m, 5H), 4.44 (d, J= 11.7 Hz, 1H), 4.38 (d, J= 11.7 Hz, 1H), 4.27 (d, J= 7.8 Hz, 1H), 3.98 (s, 2H), 3.95–3.33 (m, 11H), 2.68 (t, J= 9.6 Hz, 1H), 2.28 (s, 1H; Ar-CH3); ¹³C NMR (75 MHz, CDCl3) δ: 140.4, 138.0, 137.9, 137.5, 137.3, 132.6, 129.4, 129.0, 128.3, 128.2, 128.15, 128.08, 128.06, 127.8, 127.7, 127.65, 127.61, 127.5, 127.44, 127.40, 127.15, 126.7, and 126.68 (Ar-C), 104.2 (C’-1), 88.0 (C-1), 82.5, 81.8, 75.5, 74.3, 73.8, 73.6, 73.4, 73.3, 73.2, 72.7, 72.5, 70.9, 69.5, 68.6, 66.8, 64.6, 61.4, 53.3, 52.4, 20.9 (Ar-CH3); HRMS (ESI) calcd for C54H59NO9S [M]⁺: 897.3911, found: 897.3920.

p-Tolyl 3,4,6-Tri-O-benzyl--D-galactopyranosyl-(1→4)-N-benzyl-N-benzyloxy- carbonyl-2-amino-6-O-benzyl-2-deoxy-1-thio--D-glucopyranoside (38)

O STol O

N(Cbz)Bn HO

O OBn BnO OBn

BnO

OH 38

To a solution of compound 37 (430 mg, 0.48 mmol) and NaHCO3 (323 mg, 3.84 mmol) in non-dried MeOH (5 mL) at room temperature, was added benzyl chloroformate (0.2 mL, 0.72 mmol, 50 wt% solution in toluene). After stirring for 2h, the residue was diluted with CH2Cl2 (10 mL), poured into a two-layer mixture of CH2Cl2 (20 mL) and brine (20 mL), and the whole was extracted with CH2Cl2 (40 mL × 3). The combined organic phase was separated, dried over MgSO4, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography over silica gel (EtOAc/CH2Cl2/hexane, 1:1:4) to give 38 (405 mg,

82%) as colorless foam. Rf = 0.30 (EtOAc/CH2Cl2/hexane, 1:1:2); []³⁰D -9 (c 1.68, CHCl3). Standard ¹H and ¹³C NMR spectra were obscured by peak broadening.

6-Chlorohexyl 3,4,6-Tri-O-benzyl--D-galactopyranosyl-(1→4)-N-benzyl-N-benz- yloxycarbonyl-2-amino-6-O-benzyl-2-deoxy-1-thio--D-glucopyranoside (39)

O O O

BnO OBn BnO

OBn

HO HO

N(Cbz)Bn OR 39, R = (CH₂)₆Cl

Compound 38 (100 mg, 0.097 mmol), 6-chlorohexanol 7 (26 μL, 0.194 mmol), and activated 4 Å MS (400 mg, 100mg/1mL CH2Cl2, AW300) in CH2Cl2 (4 mL) were stirred at room temperature under nitrogen for 20 min. The mixture was then cooled in a cooling bath at 50 ^oC followed by addition of TfOH (58 L, 7 mM) and NIS (26 mg, 0.116 mmol) and stirred for 2h. After disappearance of acceptor detected by TLC, the mixture was diluted with CH2Cl2 (12 mL), quenched by Et3N, and few droplets of sat. NaHCO3 and pieces of Na2S2O3(s) were added. The quenching mixture was then stirred at room temperature for 2h, filtered and finally concentrated. The residue was purified by column chromatography over silica gel (EtOAc/CH2Cl2, 1:16→1:6) to give 39 (89 mg, 88%) as colorless foam. Rf = 0.33 (EtOAc/CH2Cl2, 1:16); []³⁰D -4 (c 1.5, CHCl3). Standard ¹H and ¹³C NMR spectra were obscured by

eak broadening.

enzyloxycarbonyl-2-amino-6-O-benzyl p

6-Chlorohexyl 2,3,4-Tri-O-benzyl--L-fucopyranosyl-(1→2)-3,4,6-tri-O-benzyl-

- -galactopyranosyl-(1→4)-N-benzyl-N-b

-2-deoxy-1-thio--D-glucopyranoside (40)

O O O

BnO OBn BnO

OBn

O HO

N(Cbz)Bn OR O OBn

BnOOBn

40, R = (CH₂)₆Cl

Compound 38 (290 mg, 2.32 mmol), 6-chlorohexanol 7 (56 μL, 0.42 mmol), and activated 4 Å MS (1.2 g, 100mg/1mL CH2Cl2, AW300) in CH2Cl2 (12 mL) were stirred at room temperature under nitrogen for 20 min. The mixture was then cooled in a cooling bath at 50 ^oC followed by addition of NIS (76 mg, 0.34 mmol) and TfOH (168 L/0.5 M ether, 0.084 mmol) and stirred for 2h. After disappearance of donor 38 detected by TLC, the temperature was cooled to 70 ^oC followed by addition of fucosyl donor 12 (453 mg, 0.84 mmol), NIS (203 mg, 0.90 mmol) and TfOH (504 L/0.5 M ether, 0.25 mmol) in sequential order. After 10 min, the temperature was raised to 60 ^oC and the reaction was stirred for 2h. After disappearance of donor 12 detected by TLC, the mixture was diluted with CH2Cl2 (24 mL), quenched by Et3N, and few droplets of sat. NaHCO3 and pieces of Na2S2O3(s)

在文檔中環胺基酸酯結合非對稱胺基保護在寡糖合成上的應用 (頁 61-0)