Reaction SMILES: [CH:1]([C:3]1[CH:4]=[C:5]([C@H:9]([NH:11][C:12]([C@@H:14]2[CH2:19][CH2:18][CH2:17][N:16]([C:20](=[O:56])[C@@H:21]([NH:37][C:38](=[O:55])[C@@H:39]([NH:43][C:44](=[O:54])[C@H:45]([CH3:53])[C@H:46]([O:51][CH3:52])[CH2:47][CH2:48]C=C)[CH:40]([CH3:42])[CH3:41])[CH2:22][C:23]3[CH:28]=[CH:27][CH:26]=[C:25]([O:29][Si:30]([C:33]([CH3:36])([CH3:35])[CH3:34])([CH3:32])[CH3:31])[CH:24]=3)[NH:15]2)=[O:13])[CH3:10])[CH:6]=[CH:7][CH:8]=1)=[CH2:2]>CC1C=C(C)C(N2C(=[Ru](Cl)(Cl)=CC3C=CC=CC=3OC(C)C)N(C3C(C)=CC(C)=CC=3C)CC2)=C(C)C=1.ClCCCl>[C:33]([Si:30]([CH3:32])([CH3:31])[O:29][C:25]1[CH:24]=[C:23]([CH:28]=[CH:27][CH:26]=1)[CH2:22][CH:21]1[NH:37][C:38](=[O:55])[CH:39]([CH:40]([CH3:41])[CH3:42])[NH:43][C:44](=[O:54])[CH:45]([CH3:53])[CH:46]([O:51][CH3:52])[CH2:47][CH2:48][CH:2]=[CH:1][C:3]2[CH:4]=[C:5]([CH:6]=[CH:7][CH:8]=2)[CH:9]([CH3:10])[NH:11][C:12](=[O:13])[CH:14]2[NH:15][N:16]([CH2:17][CH2:18][CH2:19]2)[C:20]1=[O:56])([CH3:35])([CH3:36])[CH3:34]
Reactant: C=CCC[C@@H](OC)[C@@H](C)C(=O)N[C@H](C(=O)N[C@@H](Cc1cccc(O[Si](C)(C)C(C)(C)C)c1)C(=O)N1CCC[C@@H](C(=O)N[C@H](C)c2cccc(C=C)c2)N1)C(C)C
Agent: Cc1cc(C)c(N2CCN(c3c(C)cc(C)cc3C)C2=[Ru](Cl)(Cl)=Cc2ccccc2OC(C)C)c(C)c1
Solvent: ClCCCl
Product: COC1CCC=Cc2cccc(c2)C(C)NC(=O)C2CCCN(N2)C(=O)C(Cc2cccc(O[Si](C)(C)C(C)(C)C)c2)NC(=O)C(C(C)C)NC(=O)C1C
Temperature: 80 °C
Yield: 22.1 %

Procedure:
Hoveyda-Grubbs 2nd generation catalyst (22 mg, 0.035 mmol) was added to a stirred solution of (S)-1-{(S)-3-[3-(tert-butyl-dimethyl-silanyloxy)-phenyl]-2-[(S)-2-((2R,3R)-3-methoxy-2-methyl-hept-6-enoylamino)-3-methyl-butyrylamino]-prop ionyl}-hexahydro-pyridazine-3-carboxylic acid [(R)-1-(3-vinyl-phenyl)-ethyl]-amide (276 mg, 0.35 mmol) in 1,2-dichloroethane (135 mL) and the reaction mixture was heated at 80° C. under nitrogen for 3 hours. The reaction mixture was cooled to room temperature, silica gel was added and the reaction mixture was evaporated. The residue was purified by silica gel chromatography using a gradient of iso-hexanes/ethyl acetate 1:1 to neat ethyl acetate to afford (E)-2R,5S,11S,14S,17R,18R)-11-[3-(tert-butyl-dimethyl-silanyloxy)-benzyl]-14-isopropyl-18-methoxy-2,17-dimethyl-3,9,12,15,28-pentaaza-tricyclo[21.3.1.1*5,9*]octacosa-1(27),21,23,25-tetraene-4, 10,13,16-tetraone (59 mg, 22%) as a gum. LCMS (m/z) 762 [M+H], Tr=5.01 min. A solution of (E)-(2R,5S,11S,14S,17R,18R)-11-[3-(tert-butyl-dimethyl-silanyloxy)-benzyl]-14-isopropyl-18-methoxy-2,17-dimethyl-3,9,12,15,28-penta-azaricyclo[21.3.1.1*5,9*]octacosa-1(27),21,23,25-tetraene-4,10,13,16-tetraone (59 mg, 0.077 mmol) in tetrahydrofuran (5 mL) was stirred at 0° C. under nitrogen. A solution of tetra-N-butylammonium fluoride (1 M in tetrahydrofuran, 0.12 mL, 0.123 mmol) was added and the reaction mixture was stirred at 0° C. for 10 minutes. Silica gel was added and the solvent was evaporated. The residue was purified by silica gel chromatography using a gradient of iso-hexanes/ethyl acetate 1:3 to neat ethyl acetate. The residue was triturated with ether and the resulting solid was collected, washed with ether and dried to afford the title compound (30 mg, 60%) as a white solid. 1H NMR (300 MHz, CD3CN) δ0.94 (d, J=6.7 Hz, 3H), 0.95 (d, J=6.7 Hz, 3H), 1.30 (d, J=7.1 Hz, 3H), 1.45 (d, J=6.9 Hz, 3H), 1.55-2.20 (m, 9H), 2.62-2.68 (m, 2H), 2.81-2.98 (m, 2H), 3.26-3.38 (m, 2H), 3.45 (s, 3H), 3.96 (d, J=12.2 Hz, 1H), 4.17 (t, J=8.0 Hz, 1H), 4.34-4.39 (m, 1H), 4.80-4.90 (m, 1H), 5.50-5.56 (m, 1H), 5.85 (d, J=15.8 Hz, 1H), 6.01-6.08 (m, 1H), 6.66-6.69 (m, 1H), 6.86-7.30 (m, 10H), 8.15-8.25 (br s, 1H). LCMS (m/z) 648 [M+H], Tr=4.30 min.