Reaction SMILES: Cl.C(N=C=NCCCN(C)C)C.[NH2:13][CH2:14]/[CH:15]=[CH:16]/[C:17]1[CH2:18][C@H:19]2[C:25](=[O:26])[N:24]([CH2:27][O:28][CH2:29][CH2:30][Si:31]([CH3:34])([CH3:33])[CH3:32])[C:23]3[CH:35]=[C:36]([O:41][CH2:42][CH2:43][CH2:44][O:45][C:46]4[C:47]([O:73][CH3:74])=[CH:48][C:49]5[C:55](=[O:56])[N:54]6[CH:57]=[C:58](/[CH:60]=[CH:61]/[CH3:62])[CH2:59][C@H:53]6[C:52](=[O:63])[N:51]([CH2:64][O:65][CH2:66][CH2:67][Si:68]([CH3:71])([CH3:70])[CH3:69])[C:50]=5[CH:72]=4)[C:37]([O:39][CH3:40])=[CH:38][C:22]=3[C:21](=[O:75])[N:20]2[CH:76]=1.[CH:77]1[C:89]2[CH:88]([CH2:90][O:91][C:92]([NH:94][C@@H:95]([CH:104]([CH3:106])[CH3:105])[C:96]([NH:98][C@@H:99]([CH3:103])[C:100](O)=[O:101])=[O:97])=[O:93])[C:87]3[C:82](=[CH:83][CH:84]=[CH:85][CH:86]=3)[C:81]=2[CH:80]=[CH:79][CH:78]=1>ClCCl>[CH3:40][O:39][C:37]1[C:36]([O:41][CH2:42][CH2:43][CH2:44][O:45][C:46]2[C:47]([O:73][CH3:74])=[CH:48][C:49]3[C:55](=[O:56])[N:54]4[CH:57]=[C:58](/[CH:60]=[CH:61]/[CH3:62])[CH2:59][C@H:53]4[C:52](=[O:63])[N:51]([CH2:64][O:65][CH2:66][CH2:67][Si:68]([CH3:71])([CH3:70])[CH3:69])[C:50]=3[CH:72]=2)=[CH:35][C:23]2[N:24]([CH2:27][O:28][CH2:29][CH2:30][Si:31]([CH3:34])([CH3:33])[CH3:32])[C:25](=[O:26])[C@@H:19]3[CH2:18][C:17](/[CH:16]=[CH:15]/[CH2:14][NH:13][C:100](=[O:101])[C@@H:99]([NH:98][C:96](=[O:97])[C@@H:95]([NH:94][C:92](=[O:93])[O:91][CH2:90][CH:88]4[C:89]5[CH:77]=[CH:78][CH:79]=[CH:80][C:81]=5[C:82]5[C:87]4=[CH:86][CH:85]=[CH:84][CH:83]=5)[CH:104]([CH3:106])[CH3:105])[CH3:103])=[CH:76][N:20]3[C:21](=[O:75])[C:22]=2[CH:38]=1
Reactant: CC(C)[C@H](NC(=O)OCC1c2ccccc2-c2ccccc21)C(=O)N[C@@H](C)C(=O)O
Reactant: C/C=C/C1=CN2C(=O)c3cc(OC)c(OCCCOc4cc5c(cc4OC)C(=O)N4C=C(/C=C/CN)C[C@H]4C(=O)N5COCC[Si](C)(C)C)cc3N(COCC[Si](C)(C)C)C(=O)[C@@H]2C1
Agent: CCN=C=NCCCN(C)C
Agent: Cl
Solvent: ClCCl
Product: C/C=C/C1=CN2C(=O)c3cc(OC)c(OCCCOc4cc5c(cc4OC)C(=O)N4C=C(/C=C/CNC(=O)[C@H](C)NC(=O)[C@@H](NC(=O)OCC6c7ccccc7-c7ccccc76)C(C)C)C[C@H]4C(=O)N5COCC[Si](C)(C)C)cc3N(COCC[Si](C)(C)C)C(=O)[C@@H]2C1
Temperature: 25 °C
Reaction time: 1.58 h
Yield: 50.3 %

Procedure:
1-Ethyl-3-(3′-dimethylaminopropyl)carbodiimide hydrochloride (0.0641 g, 0.334 mmol, 1.0 eq.) was added to a solution of allylamine 17c (assumed 100% yield, 0.306 g, 0.334 mmol, 1.0 eq.) and HO-Ala-Val-Fmoc 12 (0.1367 g, 0.334 mmol, 1.0 eq.) in dry dichloromethane (18 mL). The reaction mixture was stirred for 95 minutes at room temperature when the reaction mixture was diluted with dichloromethane (30 mL) and washed sequentially with water (30 mL) and brine (30 mL). The organic layer was dried over MgSO4 filtered and excess dichloromethane removed under reduced pressure. The resulting residue was purified by flash chromatography (silica gel; 100:1 v/v DCM/MeOH to 40:1 v/v DCM/MeOH) to afford the product as a yellow solid (0.220 g, 50%). LC/MS (3.804 min (ES+)), m/z: 1307.37 [M+H]+. 1H NMR (400 MHz, CDCl3) δ 7.76 (d, 2H, J=7.6 Hz), 7.57 (m, 2H), 7.39 (t, 2H, J=7.6 Hz), 7.34 (d, 2H, J=3.2 Hz), 7.31 (m, 3H), 7.26 (m, 1H), 6.93 (s, 1H), 6.85 (m, 1H), 6.36 (m, 2H), 6.24 (d, 1H, J=14.7 Hz), 5.68 (m, 1H), 5.58 (m, 1H), 5.49 (m, 2H), 4.72 (m, 2H), 4.83 (m, 4H), 4.39 (m, 1H), 4.27 (m, 4H), 4.22 (t, 1H, J=6.9 Hz), 3.98 (m, 3H), 3.89 (m, 8H), 3.75 (m, 2H), 3.65 (m, 4H), 2.85 (m, 2H), 2.43 (m, 2H), 2.14 (m, 1H), 1.82 (dd, 3H, J=5.8, 0.8 Hz), 1.40 (d, 3H, J=6.9 Hz), 0.99-0.92 (m, 10H), 0.01 (s, 9H), 0.00 (s, 9H).