Reaction SMILES: C([N+](CCCC)(CCCC)CCCC)CCC.[P:18]([O:22][CH2:23][C@@H:24]1[C@@H:28]([O:29][P:30]([O:33][CH2:34][C@@H:35]2[C@@H:39]([OH:40])[C@@H:38]([OH:41])[C@H:37]([N:42]3[CH:50]=[N:49][C:48]4[C:43]3=[N:44][CH:45]=[N:46][C:47]=4[NH2:51])[O:36]2)([OH:32])=[O:31])[CH2:27][C@H:26]([N:52]2[CH:57]=[CH:56][C:55]([NH2:58])=[N:54][C:53]2=[O:59])[O:25]1)([OH:21])([OH:20])=[O:19].C(OC([NH:67][C@@H:68]([CH2:75][C:76]([O:78][C:79]1[C:84]([CH3:85])=[CH:83][CH:82]=[CH:81][C:80]=1[S:86][S:87][CH2:88][CH3:89])=[O:77])[C:69](OCC#N)=[O:70])=O)(C)(C)C.C[N+](C)(C)CCCCCCCCCCCCCCCC>O.O1CCCC1.FC(F)(F)C(O)=O>[NH2:67][C@@H:68]([CH2:75][C:76]([O:78][C:79]1[C:84]([CH3:85])=[CH:83][CH:82]=[CH:81][C:80]=1[S:86][S:87][CH2:88][CH3:89])=[O:77])[C:69]([O:40][C@H:39]1[C@@H:38]([OH:41])[C@H:37]([N:42]2[CH:50]=[N:49][C:48]3[C:43]2=[N:44][CH:45]=[N:46][C:47]=3[NH2:51])[O:36][C@@H:35]1[CH2:34][O:33][P:30]([O:29][C@H:28]1[CH2:27][C@H:26]([N:52]2[CH:57]=[CH:56][C:55]([NH2:58])=[N:54][C:53]2=[O:59])[O:25][C@@H:24]1[CH2:23][O:22][P:18]([OH:21])([OH:20])=[O:19])([OH:32])=[O:31])=[O:70]
Reactant: CCSSc1cccc(C)c1OC(=O)C[C@H](NC(=O)OC(C)(C)C)C(=O)OCC#N
Reactant: Nc1ccn([C@H]2C[C@H](OP(=O)(O)OC[C@H]3O[C@@H](n4cnc5c(N)ncnc54)[C@H](O)[C@@H]3O)[C@@H](COP(=O)(O)O)O2)c(=O)n1
Agent: CCCCCCCCCCCCCCCC[N+](C)(C)C
Agent: CCCC[N+](CCCC)(CCCC)CCCC
Solvent: O
Solvent: C1CCOC1
Solvent: O=C(O)C(F)(F)F
Product: CCSSc1cccc(C)c1OC(=O)C[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
Temperature: 25 °C
Reaction time: 1.5 h
Yield: 4 %

Procedure:
A solution of ((2R,3S,5R)-5-(4-amino-2-oxopyrimidin-1(2H)-yl)-3-(((((2R,3S,4R,5R)-5-(6-amino-9H-purin-9-yl)-3,4-dihydroxytetrahydrofuran-2-yl)methoxy) (hydroxy)phosphoryl)oxy)tetrahydrofuran-2-yl)methyl dihydrogenphosphate (pdCpA, Compound 1h) (49.0 mg, 0.077 mmol) in water (1.52 ml) and a solution of 1-(cyanomethyl) 4-(2-(ethyldisulfanyl)-6-methylphenyl) (S)-2-((tert-butoxycarbonyl)amino)succinate (140 mg, 0.308 mmol) in tetrahydrofuran (0.764 ml) were added to buffer A (29.2 ml), and the mixture was stirred at room temperature for 1.5 hours. Trifluoroacetic acid (0.396 ml, 5.37 mmol) was then added, followed by lyophilization. The resulting residue was purified by reverse-phase silica gel column chromatography (0.1% aqueous formic acid solution/0.1% formic acid-acetonitrile solution=100/0→50/50) to afford a mixture of 1-((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) 4-(2-(ethyldisulfanyl)-6-methylphenyl) (2S)-2-((tert-butoxycarbonyl)amino) succinate and N,N,N-trimethylhexadecan-1-aminium. The resulting mixture was dissolved in trifluoroacetic acid (0.10 ml), and the mixture was stirred at room temperature for 10 minutes, after which the reaction solution was concentrated under reduced pressure. The resulting residue was purified by reverse-phase silica gel column chromatography (0.1% aqueous formic acid solution/0.1% formic acid-acetonitrile solution=100/0→60/40) to afford 1-((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) 4-(2-(ethyldisulfanyl)-6-methylphenyl) (2S)-2-aminosuccinate (Compound 114) (2.9 mg, 40%).