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:71][CH3:72])=[CH:48][C:49]5[C:55](=[O:56])[N:54]6[CH:57]=[C:58]([CH3:60])[CH2:59][C@H:53]6[C:52](=[O:61])[N:51]([CH2:62][O:63][CH2:64][CH2:65][Si:66]([CH3:69])([CH3:68])[CH3:67])[C:50]=5[CH:70]=4)[C:37]([O:39][CH3:40])=[CH:38][C:22]=3[C:21](=[O:73])[N:20]2[CH:74]=1.[CH:75]1[C:87]2[CH:86]([CH2:88][O:89][C:90]([NH:92][C@@H:93]([CH:102]([CH3:104])[CH3:103])[C:94]([NH:96][C@@H:97]([CH3:101])[C:98](O)=[O:99])=[O:95])=[O:91])[C:85]3[C:80](=[CH:81][CH:82]=[CH:83][CH:84]=3)[C:79]=2[CH:78]=[CH:77][CH:76]=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:71][CH3:72])=[CH:48][C:49]3[C:55](=[O:56])[N:54]4[CH:57]=[C:58]([CH3:60])[CH2:59][C@H:53]4[C:52](=[O:61])[N:51]([CH2:62][O:63][CH2:64][CH2:65][Si:66]([CH3:68])([CH3:67])[CH3:69])[C:50]=3[CH:70]=2)=[CH:35][C:23]2[N:24]([CH2:27][O:28][CH2:29][CH2:30][Si:31]([CH3:32])([CH3:34])[CH3:33])[C:25](=[O:26])[C@@H:19]3[CH2:18][C:17](/[CH:16]=[CH:15]/[CH2:14][NH:13][C:98](=[O:99])[C@@H:97]([NH:96][C:94](=[O:95])[C@H:93]([NH:92][C:90](=[O:91])[O:89][CH2:88][CH:86]4[C:87]5[CH:75]=[CH:76][CH:77]=[CH:78][C:79]=5[C:80]5[C:85]4=[CH:84][CH:83]=[CH:82][CH:81]=5)[CH:102]([CH3:104])[CH3:103])[CH3:101])=[CH:74][N:20]3[C:21](=[O:73])[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: COc1cc2c(cc1OCCCOc1cc3c(cc1OC)C(=O)N1C=C(/C=C/CN)C[C@H]1C(=O)N3COCC[Si](C)(C)C)N(COCC[Si](C)(C)C)C(=O)[C@@H]1CC(C)=CN1C2=O
Agent: CCN=C=NCCCN(C)C
Agent: Cl
Solvent: ClCCl
Product: COc1cc2c(cc1OCCCOc1cc3c(cc1OC)C(=O)N1C=C(/C=C/CNC(=O)[C@H](C)NC(=O)[C@H](NC(=O)OCC4c5ccccc5-c5ccccc54)C(C)C)C[C@H]1C(=O)N3COCC[Si](C)(C)C)N(COCC[Si](C)(C)C)C(=O)[C@@H]1CC(C)=CN1C2=O
Temperature: 25 °C
Reaction time: 2 h
Yield: 41 %

Procedure:
1-Ethyl-3-(3′-dimethylaminopropyl)carbodiimide hydrochloride (0.018 g, 0.095 mmol, 1.0 eq.) was added to a solution of allylamine 17a (assumed 100% yield, 0.100 g, 0.095 mmol, 1.0 eq.) and HO-Ala-Val-Fmoc 12 (0.036 g, 0.095 mmol, 1.0 eq.) in dry dichloromethane (6 mL). The reaction mixture was stirred for 120 minutes at room temperature when the reaction mixture was diluted with dichloromethane (10 mL) and washed sequentially with water (10 mL) and brine (10 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 (0.050 g, 35%). LC/MS (3.677 min (ES+)), m/z: 1281.42 [M+H]+. 1H NMR (400 MHz, CDCl3) δ 7.76 (d, 2H, J=7.7 Hz), 7.58 (m, 2H), 7.40 (t, 2H, J=7.6 Hz), 7.34 (d, 2H, J=5.7 Hz), 7.31 (m, 3H), 7.25 (m, 2H), 6.93 (s, 1H), 6.68 (m, 1H), 6.34 (m, 3H), 5.58 (m, 1H), 5.49 (m, 2H), 4.71 (m, 2H), 4.45 (m, 5H), 4.27 (m, 4H), 4.22 (t, 1H, J=7.0 Hz), 3.97 (m, 2H), 3.89 (m, 7H), 3.75 (m, 2H), 3.65 (m, 3H), 3.44 (m, 1H), 2.77 (m, 2H), 2.43 (m, 2H), 2.14 (m, 1H), 1.83 (d, 3H, J=1.0 Hz), 1.40 (d, 3H, J=6.9 Hz), 0.99-0.91 (m, 10H), 0.01 (s, 9H), 0.00 (s, 9H).