Reaction SMILES: FC(F)(F)C(O)=O.[N:8]([C:11]1[CH:81]=[CH:80][C:14]([CH2:15][O:16][C:17]([NH:19][CH2:20][C@H:21]([S:77][S:78][CH3:79])[CH2:22][CH2:23][C@@H:24]([NH:69]C(OC(C)(C)C)=O)[C:25]([O:27][C@H:28]2[C@@H:32]([OH:33])[C@@H:31]([N:34]3[CH:42]=[N:41][C:40]4[C:35]3=[N:36][CH:37]=[N:38][C:39]=4[NH2:43])[O:30][C@H:29]2[CH2:44][O:45][P:46]([O:49][C@H:50]2[CH2:54][C@H:53]([N:55]3[CH:60]=[CH:59][C:58]([NH2:61])=[N:57][C:56]3=[O:62])[O:52][C@@H:51]2[CH2:63][O:64][P:65]([OH:68])([OH:67])=[O:66])([OH:48])=[O:47])=[O:26])=[O:18])=[CH:13][CH:12]=1)=[N+:9]=[N-:10]>ClCCl>[NH2:69][C@H:24]([CH2:23][CH2:22][C@@H:21]([S:77][S:78][CH3:79])[CH2:20][NH:19][C:17]([O:16][CH2:15][C:14]1[CH:13]=[CH:12][C:11]([N:8]=[N+:9]=[N-:10])=[CH:81][CH:80]=1)=[O:18])[C:25]([O:27][C@H:28]1[C@@H:32]([OH:33])[C@@H:31]([N:34]2[CH:42]=[N:41][C:40]3[C:35]2=[N:36][CH:37]=[N:38][C:39]=3[NH2:43])[O:30][C@H:29]1[CH2:44][O:45][P:46]([O:49][C@H:50]1[CH2:54][C@H:53]([N:55]2[CH:60]=[CH:59][C:58]([NH2:61])=[N:57][C:56]2=[O:62])[O:52][C@@H:51]1[CH2:63][O:64][P:65]([OH:68])([OH:67])=[O:66])([OH:48])=[O:47])=[O:26].[NH2:69][C@H:24]([CH2:23][CH2:22][C@@H:21]([S:77][S:78][CH3:79])[CH2:20][NH2:19])[C:25]([O:27][C@H:28]1[C@@H:32]([OH:33])[C@@H:31]([N:34]2[CH:42]=[N:41][C:40]3[C:35]2=[N:36][CH:37]=[N:38][C:39]=3[NH2:43])[O:30][C@H:29]1[CH2:44][O:45][P:46]([O:49][C@H:50]1[CH2:54][C@H:53]([N:55]2[CH:60]=[CH:59][C:58]([NH2:61])=[N:57][C:56]2=[O:62])[O:52][C@@H:51]1[CH2:63][O:64][P:65]([OH:67])([OH:68])=[O:66])([OH:48])=[O:47])=[O:26]
Reactant: CSS[C@H](CC[C@@H](NC(=O)OC(C)(C)C)C(=O)O[C@H]1[C@@H](O)[C@@H](n2cnc3c(N)ncnc32)O[C@H]1COP(=O)(O)O[C@H]1C[C@H](n2ccc(N)nc2=O)O[C@@H]1COP(=O)(O)O)CNC(=O)OCc1ccc(N=[N+]=[N-])cc1
Solvent: ClCCl
Solvent: O=C(O)C(F)(F)F
Product: CSS[C@@H](CN)CC[C@@H](N)C(=O)O[C@H]1[C@@H](O)[C@@H](n2cnc3c(N)ncnc32)O[C@H]1COP(=O)(O)O[C@H]1C[C@H](n2ccc(N)nc2=O)O[C@@H]1COP(=O)(O)O
Product: CSS[C@H](CC[C@@H](N)C(=O)O[C@H]1[C@@H](O)[C@@H](n2cnc3c(N)ncnc32)O[C@H]1COP(=O)(O)O[C@H]1C[C@H](n2ccc(N)nc2=O)O[C@@H]1COP(=O)(O)O)CNC(=O)OCc1ccc(N=[N+]=[N-])cc1
Temperature: 25 °C
Reaction time: 0.5 h
Yield: 25 %
Yield: 14 %

Procedure:
A 10% solution of trifluoroacetic acid in dichloromethane (0.24 mL) was added to a solution of (2S,5S)-(2R,3S,4R,5R)-2-((((((2R,3S,5R)-5-(4-amino-2-oxopyrimidin-1(2H)-yl)-2-((phosphonooxy)methyl)tetrahydrofuran-3-yl)oxy)(hydroxy)phosphoryl)oxy)methyl)-5-(6-amino-9H-purin-9-yl)-4-hydroxytetrahydrofuran-3-yl 6-((((4-azidobenzyl)oxy)carbonyl)amino)-2-((tert-butoxycarbonyl)amino)-5-(methyldisulfanyl)hexanoate (Compound tk10) (14.0 mg, 0.013 mmol) in dichloromethane (0.2 mL), and the mixture was stirred at room temperature for 30 minutes. Following concentration under reduced pressure, the resulting residue was purified by reverse-phase silica gel column chromatography (0.05% aqueous trifluoroacetic acid solution/0.05% trifluoroacetic acid-acetonitrile solution) to afford (2S,5S)-(2R,3S,4R,5R)-2-((((((2R,3S,5R)-5-(4-amino-2-oxopyrimidin-1(2H)-yl)-2-((phosphonooxy)methyl)tetrahydrofuran-3-yl)oxy)(hydroxy)phosphoryl)oxy)methyl)-5-(6-amino-9H-purin-9-yl)-4-hydroxytetrahydrofuran-3-yl 2-amino-6-((((4-azidobenzyl)oxy)carbonyl)amino)-5-(methyldisulfanyl)hexanoate (Lys(5S-SSMe)(Acbz)-pdCpA) (Compound tk11) (3.2 mg, 25%) and (2S,5S)-(2R,3S,4R,5R)-2-((((((2R,3S,5R)-5-(4-amino-2-oxopyrimidin-1(2H)-yl)-2-((phosphonooxy)methyl)tetrahydrofuran-3-yl)oxy)(hydroxy)phosphoryl)oxy)methyl)-5-(6-amino-9H-purin-9-yl)-4-hydroxytetrahydrofuran-3-yl 2,6-diamino-5-(methyldisulfanyl)hexanoate (Lys(5S-SSMe)-pdCpA) (Compound tk12) (1.5 mg, 14%).