Reaction SMILES: [CH2:1]([O:8][CH2:9][O:10][C@H:11]([CH3:88])[C@H:12]([O:80][Si](C(C)(C)C)(C)C)[CH2:13][C@H:14]1[O:19][C@:18]([C:22]([CH3:64])([CH3:63])/[CH:23]=[CH:24]/[C@@H:25]2[O:30][C@H:29]([CH2:31][C@@H:32]3[O:37][C@H:36]([CH2:38][C@@H:39]([O:44][CH2:45][C:46]4[CH:51]=[CH:50][C:49]([O:52][CH3:53])=[CH:48][CH:47]=4)[CH2:40][C:41]([OH:43])=[O:42])[CH2:35][C@H:34]([O:54][Si](C(C)(C)C)(C)C)[CH2:33]3)[CH2:28][C:27](=[CH2:62])[CH2:26]2)([O:20][CH3:21])[C@@H:17]([O:65][C:66](=[O:74])[CH2:67][CH2:68][CH2:69][CH2:70][CH2:71][CH2:72][CH3:73])/[C:16](=[CH:75]/[C:76]([O:78][CH3:79])=[O:77])/[CH2:15]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1>C1COCC1.N1C=CC=CC=1>[CH2:1]([O:8][CH2:9][O:10][C@H:11]([CH3:88])[C@H:12]([OH:80])[CH2:13][C@H:14]1[O:19][C@:18]([C:22]([CH3:64])([CH3:63])/[CH:23]=[CH:24]/[C@@H:25]2[O:30][C@H:29]([CH2:31][C@@H:32]3[O:37][C@H:36]([CH2:38][C@@H:39]([O:44][CH2:45][C:46]4[CH:47]=[CH:48][C:49]([O:52][CH3:53])=[CH:50][CH:51]=4)[CH2:40][C:41]([OH:43])=[O:42])[CH2:35][C@H:34]([OH:54])[CH2:33]3)[CH2:28][C:27](=[CH2:62])[CH2:26]2)([O:20][CH3:21])[C@@H:17]([O:65][C:66](=[O:74])[CH2:67][CH2:68][CH2:69][CH2:70][CH2:71][CH2:72][CH3:73])/[C:16](=[CH:75]/[C:76]([O:78][CH3:79])=[O:77])/[CH2:15]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1
Reactant: C=C1C[C@@H](C[C@H]2C[C@@H](O[Si](C)(C)C(C)(C)C)C[C@@H](C[C@H](CC(=O)O)OCc3ccc(OC)cc3)O2)O[C@@H](/C=C/C(C)(C)[C@]2(OC)O[C@H](C[C@@H](O[Si](C)(C)C(C)(C)C)[C@@H](C)OCOCc3ccccc3)C/C(=C\C(=O)OC)[C@@H]2OC(=O)CCCCCCC)C1
Solvent: c1ccncc1
Solvent: C1CCOC1
Product: C=C1C[C@@H](C[C@H]2C[C@@H](O)C[C@@H](C[C@H](CC(=O)O)OCc3ccc(OC)cc3)O2)O[C@@H](/C=C/C(C)(C)[C@]2(OC)O[C@H](C[C@@H](O)[C@@H](C)OCOCc3ccccc3)C/C(=C\C(=O)OC)[C@@H]2OC(=O)CCCCCCC)C1
Temperature: 25 °C
Reaction time: 48 h
Yield: 86.8 %

Procedure:
To a stirring solution of TBS ether 10 (7.6 mg, 0.0060 mmol, 1.0 equiv) in 9:1 THF/pyridine (600 μL, 0.01 M) in a 4 mL plastic vial was added HF.Py (20%, 240 μL). The solution was stirred at rt for 48 h, then diluted with 50% EtOAc/hexanes (50 mL), and washed with brine (2×10 mL). The solution was dried over Na2SO4, and concentrated under reduced pressure. Purification was accomplished using flash column chromatography with a 2×14 cm silica gel column, eluting with 10% MeOH/40% EtOAc/hexanes, collecting 10×130 mm test tube fractions. The product containing fractions (6-8) were combined and concentrated under reduced pressure to provide pure product 21 (5.4 mg, 87%) as a colorless oil. Rf=0.48 (MeOH/EtOAc/Hexanes=10:40:50); [α]D20=+6 (c=0.20, CHCl3); 500 MHz 1H NMR (CDCl3) δ 7.37-7.29 (m, 5H), 7.25 (d, J=8.8 Hz, 2H), 6.88 (d, J=8.8 Hz, 2H), 6.00 (d, J=16.1 Hz, 1H), 5.87 (s, 1H), 5.54 (s, 1H), 5.40 (dd, J=16.1, 6.4 Hz, 1H), 4.89 (d, J=7.3 Hz, 1H), 4.84 (d, J=7.3 Hz, 1H), 4.70 (s, 2H), 4.66 (d, J=2.9 Hz, 2H), 4.57 (d, J=10.7 Hz, 1H), 4.46 (d, J=10.7 Hz, 1H), 4.22-4.16 (m, 1H), 4.14-4.06 (m, 2H), 3.86 (m, 1H), 3.80 (s, 3H), 3.78-3.72 (m, 1H), 3.70-3.62 (m, 5H), 3.52-3.40 (m, 4H), 3.33 (s, 3H), 2.61 (dddd, J=15.6, 15.6, 15.6, 5.9 Hz, 2H), 2.40-2.32 (m, 3H), 2.22 (t, J=14.6 Hz, 3H), 2.05-1.85 (m, 5H), 1.80-1.55 (m, 7H), 1.34-1.24 (m, 10H), 1.18-1.08 (m, 9H), 0.90-0.87 (m, 3H); 125 MHz 13C NMR (CDCl3) δ 173.5, 172.3, 166.9, 159.6, 153.2, 144.4, 139.7, 137.7, 130.2, 129.7, 128.7, 128.1, 128.1, 127.0, 116.8, 114.2, 109.1, 102.9, 93.9, 80.0, 77.9, 75.1, 72.9, 72.5, 72.2, 72.2, 71.3, 70.1, 68.2, 68.2, 60.6, 55.5, 51.5, 51.4, 46.2, 42.2, 41.8, 41.5, 41.1, 40.8, 40.8, 39.9, 34.7, 31.9, 29.9, 29.3, 29.1, 25.0, 24.9, 24.9, 23.0, 22.8, 17.0, 14.3; 125 MHz DEPT 13C NMR (CDCl3) CH3 δ 55.5, 51.5, 51.4, 25.0, 23.0, 17.0, 14.3; CH2 δ 109.1, 93.9, 72.2, 70.1, 42.2, 41.8, 41.5, 41.1, 40.8, 40.8, 39.9, 34.7, 31.9, 29.9, 29.3, 29.1, 24.9, 24.9, 22.8; CH δ 139.7, 129.7, 128.7, 128.1, 128.1, 127.0, 116.8, 114.2, 80.0, 77.9, 75.1, 72.9, 72.5, 72.2, 72.2, 71.3, 68.2, 68.2; C δ 173.5, 172.3, 166.9, 159.6, 153.3, 144.4, 137.7, 130.2, 102.9, 46.2; IR (neat) 3426, 2930, 1719, 1514, 1458, 1379, 1247, 1156, 1105, 1038, 745 cm−1; HRMS (ESI/APCI) calcd C58H84O16Na for (M+Na) 1059.5657. found 1059.5675.