Reaction SMILES: [C:1]([O:9][C@H:10]1[C@@H:15]([O:16][C:17](=[O:24])[C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)[C@H:14]([O:25][C:26](=[O:33])[C:27]2[CH:32]=[CH:31][CH:30]=[CH:29][CH:28]=2)[C@@H:13]([CH2:34][O:35][C:36](=[O:43])[C:37]2[CH:42]=[CH:41][CH:40]=[CH:39][CH:38]=2)[O:12][C@@H:11]1[O:44][C@H:45]1[C@H:50]([O:51][C:52](=[O:59])[C:53]2[CH:58]=[CH:57][CH:56]=[CH:55][CH:54]=2)[C@@H:49]([CH2:60][O:61][C:62](=[O:69])[C:63]2[CH:68]=[CH:67][CH:66]=[CH:65][CH:64]=2)[O:48][C@H:47]([O:70][C@H:71]2[C@H:77]([O:78][C:79](=[O:86])[C:80]3[CH:85]=[CH:84][CH:83]=[CH:82][CH:81]=3)[C@@H:76]([CH2:87][O:88][C:89](=[O:96])[C:90]3[CH:95]=[CH:94][CH:93]=[CH:92][CH:91]=3)[O:75][CH:73]([OH:74])[C@H:72]2[O:97][C:98](=[O:105])[C:99]2[CH:104]=[CH:103][CH:102]=[CH:101][CH:100]=2)[C@H:46]1[O:106][C:107](=[O:114])[C:108]1[CH:113]=[CH:112][CH:111]=[CH:110][CH:109]=1)(=[O:8])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[Cl:115][C:116]([Cl:120])([Cl:119])[C:117]#[N:118].CCCCCC.CCOC(C)=O>C(Cl)Cl.C1CCN2C(=NCCC2)CC1>[Cl:115][C:116]([Cl:120])([Cl:119])[C:117](=[NH:118])[O:74][CH:73]1[O:75][C@H:76]([CH2:87][O:88][C:89](=[O:96])[C:90]2[CH:95]=[CH:94][CH:93]=[CH:92][CH:91]=2)[C@@H:77]([O:78][C:79](=[O:86])[C:80]2[CH:81]=[CH:82][CH:83]=[CH:84][CH:85]=2)[C@H:71]([O:70][C@H:47]2[O:48][C@H:49]([CH2:60][O:61][C:62](=[O:69])[C:63]3[CH:68]=[CH:67][CH:66]=[CH:65][CH:64]=3)[C@@H:50]([O:51][C:52](=[O:59])[C:53]3[CH:58]=[CH:57][CH:56]=[CH:55][CH:54]=3)[C@H:45]([O:44][C@H:11]3[O:12][C@H:13]([CH2:34][O:35][C:36](=[O:43])[C:37]4[CH:38]=[CH:39][CH:40]=[CH:41][CH:42]=4)[C@@H:14]([O:25][C:26](=[O:33])[C:27]4[CH:32]=[CH:31][CH:30]=[CH:29][CH:28]=4)[C@H:15]([O:16][C:17](=[O:24])[C:18]4[CH:19]=[CH:20][CH:21]=[CH:22][CH:23]=4)[C@@H:10]3[O:9][C:1](=[O:8])[C:2]3[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=3)[C@@H:46]2[O:106][C:107](=[O:114])[C:108]2[CH:113]=[CH:112][CH:111]=[CH:110][CH:109]=2)[C@@H:72]1[O:97][C:98](=[O:105])[C:99]1[CH:100]=[CH:101][CH:102]=[CH:103][CH:104]=1
Reactant: O=C(OC[C@H]1O[C@H](O[C@@H]2[C@H](OC(=O)c3ccccc3)[C@@H](O[C@H]3[C@H](OC(=O)c4ccccc4)[C@@H](COC(=O)c4ccccc4)OC(O)[C@H]3OC(=O)c3ccccc3)O[C@H](COC(=O)c3ccccc3)[C@H]2OC(=O)c2ccccc2)[C@@H](OC(=O)c2ccccc2)[C@@H](OC(=O)c2ccccc2)[C@@H]1OC(=O)c1ccccc1)c1ccccc1
Reactant: N#CC(Cl)(Cl)Cl
Solvent: CCOC(C)=O
Solvent: C1CCC2=NCCCN2CC1
Solvent: CCCCCC
Product: N=C(OC1O[C@H](COC(=O)c2ccccc2)[C@@H](OC(=O)c2ccccc2)[C@H](O[C@H]2O[C@H](COC(=O)c3ccccc3)[C@@H](OC(=O)c3ccccc3)[C@H](O[C@H]3O[C@H](COC(=O)c4ccccc4)[C@@H](OC(=O)c4ccccc4)[C@H](OC(=O)c4ccccc4)[C@@H]3OC(=O)c3ccccc3)[C@@H]2OC(=O)c2ccccc2)[C@@H]1OC(=O)c1ccccc1)C(Cl)(Cl)Cl
Temperature: 0 °C
Reaction time: 4 h
Yield: 72.2 %

Procedure:
The hemiacetal 52 (330 mg, 0.214 mmol) was dissolved in anhydrous DCM (1.1 mL, 0.2 M). To the solution was added trichloroacetonitrile (43 μL, 0.427 mmol, 2 eq). The mixture was stirred at 0° C. while a solution of DBU (1.6 μL, 0.05 eq, 0.0107 mmol) in anhydrous DCM (0.15 mL) was added. The mixture was stirred at 0° C. for 4 h and TLC (hexane-EtOAc=65:35) indicated the complete conversion. The crude was evaporated onto silica gel and purified by silica column chromatography (2×14 cm, gradient elution with hexane-EtOAc 200:20, 150:30, 120:30, 150:50 and hexane-EtOAc-Et3N 140:70:0.3) to give the trichloroacetimidate 53 as white foam (261 mg, 72%) which was used directly in the next step without further characterization.