Reaction SMILES: [CH2:1]([P:8]([CH2:18][CH2:19][CH2:20][CH2:21][CH2:22][CH2:23][CH2:24][CH2:25][CH2:26][CH2:27][CH2:28][CH2:29][CH2:30][CH2:31][CH2:32][CH2:33][CH2:34][CH3:35])(N(C(C)C)C(C)C)([O-:10])[O-:9])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[CH2:36]([O:43][C@H:44]1[C@@H:49]([O:50][CH2:51][C:52]2[CH:57]=[CH:56][CH:55]=[CH:54][CH:53]=2)[C@H:48]([O:58][CH2:59][C:60]2[CH:65]=[CH:64][CH:63]=[CH:62][CH:61]=2)[C@@H:47]([CH2:66][O:67][CH2:68][C:69]2[CH:74]=[CH:73][CH:72]=[CH:71][CH:70]=2)[O:46][C@@H:45]1[O:75][CH2:76][CH:77]([CH2:79][O:80][C@H:81]1[O:110][C@H:109]([CH2:111][O:112][CH2:113][C:114]2[CH:119]=[CH:118][CH:117]=[CH:116][CH:115]=2)[C@@H:100]([O:101][CH2:102][C:103]2[CH:108]=[CH:107][CH:106]=[CH:105][CH:104]=2)[C@H:91]([O:92][CH2:93][C:94]2[CH:99]=[CH:98][CH:97]=[CH:96][CH:95]=2)[C@@H:82]1[O:83][CH2:84][C:85]1[CH:90]=[CH:89][CH:88]=[CH:87][CH:86]=1)O)[C:37]1[CH:42]=[CH:41][CH:40]=[CH:39][CH:38]=1.N1C=NN=N1.C1C=C(Cl)C=C(C(OO)=O)C=1>ClCCl>[CH2:1]([P:8]([O:9][CH:77]([CH2:79][O:80][C@H:81]1[O:110][C@H:109]([CH2:111][O:112][CH2:113][C:114]2[CH:119]=[CH:118][CH:117]=[CH:116][CH:115]=2)[C@@H:100]([O:101][CH2:102][C:103]2[CH:104]=[CH:105][CH:106]=[CH:107][CH:108]=2)[C@H:91]([O:92][CH2:93][C:94]2[CH:95]=[CH:96][CH:97]=[CH:98][CH:99]=2)[C@@H:82]1[O:83][CH2:84][C:85]1[CH:86]=[CH:87][CH:88]=[CH:89][CH:90]=1)[CH2:76][O:75][C@H:45]1[O:46][C@H:47]([CH2:66][O:67][CH2:68][C:69]2[CH:74]=[CH:73][CH:72]=[CH:71][CH:70]=2)[C@@H:48]([O:58][CH2:59][C:60]2[CH:61]=[CH:62][CH:63]=[CH:64][CH:65]=2)[C@H:49]([O:50][CH2:51][C:52]2[CH:57]=[CH:56][CH:55]=[CH:54][CH:53]=2)[C@@H:44]1[O:43][CH2:36][C:37]1[CH:42]=[CH:41][CH:40]=[CH:39][CH:38]=1)([CH2:18][CH2:19][CH2:20][CH2:21][CH2:22][CH2:23][CH2:24][CH2:25][CH2:26][CH2:27][CH2:28][CH2:29][CH2:30][CH2:31][CH2:32][CH2:33][CH2:34][CH3:35])=[O:10])[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1
Reactant: CCCCCCCCCCCCCCCCCCP([O-])([O-])(Cc1ccccc1)N(C(C)C)C(C)C
Reactant: OC(CO[C@H]1O[C@H](COCc2ccccc2)[C@@H](OCc2ccccc2)[C@H](OCc2ccccc2)[C@@H]1OCc1ccccc1)CO[C@H]1O[C@H](COCc2ccccc2)[C@@H](OCc2ccccc2)[C@H](OCc2ccccc2)[C@@H]1OCc1ccccc1
Agent: O=C(OO)c1cccc(Cl)c1
Agent: c1nnn[nH]1
Solvent: ClCCl
Product: CCCCCCCCCCCCCCCCCCP(=O)(Cc1ccccc1)OC(CO[C@H]1O[C@H](COCc2ccccc2)[C@@H](OCc2ccccc2)[C@H](OCc2ccccc2)[C@@H]1OCc1ccccc1)CO[C@H]1O[C@H](COCc2ccccc2)[C@@H](OCc2ccccc2)[C@H](OCc2ccccc2)[C@@H]1OCc1ccccc1
Temperature: 25 °C
Reaction time: 2 h
Yield: 64.3 %

Procedure:
A solution of the phosphoramidite 45 (54 mg, 0.105 mmol) in dichloromethane (12 mL) was cannulated onto a mixture of the alcohol 12 (80 mg, 0.070 mmol) and 1H-tetrazole (11 mg, 0.161 mmol) under argon. The reaction mixture was stirred at RT for 2 hrs then cooled in ice when a solution of MCPBA (75%, 25 mg, 0.141 mmol), pre-dried for 20 min over MgSO4, was added to the reaction mixture. After a further 1 hr the reaction mixture was diluted with dichloromethane (30 mL) and quenched with the addition of 10% aqueous Na2S2O3 (45 mL). The aqueous phase was further extracted with dichloromethane (35 mL) and the combined organic extract washed with sat. NaHCO3 (2×40 mL) and dried (MgSO4). After filtration the solvent was removed at reduced pressure to give the crude product that was purified by column chromatography on silica gel. Gradient elution with ethyl acetate/petroleum ether (10:90→30:70) afforded the title compound 46 (70 mg, 0.045 mmol, 64%) as a thin film; [α]D18 +31 (c 0.54, CHCl3); 1H NMR (300 MHz, CDCl3) δ 7.40-7.10 (m, 45H), 4.97-4.40 (m, 21H), 4.00-3.55 (m, 18H), 1.51-1.42 (m, 2H), 1.30-1.15 (m, 30H), 0.88-0.81 (m, 3H); 13C NMR (75 MHz, CDCl3) δ 138.8, 128.9, 128.7, 128.3, 128.1, 127.9, 127.9, 99.0, 98.4, 80.6, 75.9, 75.4, 75.2, 75.1, 73.7, 73.0, 72.6, 72.4, 69.5, 68.5, 67.2, 66.9, 32.3, 30.6, 30.5, 30.1, 29.9, 29.7, 29.6, 25.8, 23.1, 14.5; 31P NMR (121.2 MHz, CDCl3) δ −0.12; HRMS-ESI (+ve) (Found: m/z 1576.8426 (MNH4+), C96H123NO16P requires m/z 1576.8579).