## 2 Materials and Methods
### Synthesis of L-Glutamine Derivative **4** and **5**  
2.3.1. 5-(-(2-(2-(-Azidoethoxy)ethoxy)ethoxy)pent-1-ene **19**  
To a solution of tosylate **14** (1976 mg, 5.3 mmol) in dry DMF (35 mL), 15.9 mmol of NaN\({}_{3}\) was added. The reaction was stirred at r.t. for 2 h and then at 80 \({}^{\circ}\)C for 10 h. The reaction was followed by TLC (Hexane/EtOAc 8:2). At the end of the reaction, the suspension was diluted with water and extracted with EtOAc (3\(\times\)). The organic phases were combined, dried over sodium sulphate and evaporated. The residue was purified by flash chromatography (silica gel, eluent: Hexane/EtOAc 8:2), affording azide **19** (1012 mg, 4.16 mmol, 78% yield). \({}^{1}\)H NMR (400 MHz, CDCl\({}_{3}\)) 8 5.80 (ddt, J = 16.9, 10.2, 6.7 Hz, 1H, H4), 5.01 (dd, J = 17.1, 1.6 Hz, 1H, H5a), 4.95 (d, J = 10.2 Hz, 1H, H5b), 3.72-3.61 (m, 8H, -OCH\({}_{2}\)CH\({}_{2}\)-), 3.61-3.54 (m, 2H, -OCH\({}_{2}\)CH\({}_{2}\)-), 3.46 (t, J = 6.7 Hz, 2H, H1a), 3.38 (t, J = 5.0 Hz, 2H, -OCH\({}_{2}\)CH\({}_{2}\)N\({}_{3}\)), 2.10 (q, J = 7.3 Hz, 2H, H3a,b) and 1.73-1.61 (m, 2H, H2a,b). \({}^{13}\)C NMR (101 MHz, CDCl\({}_{3}\)) 8 138.40 (C4), 114.80 (C5), 70.82, 70.81, 70.77, 70.21 and 70.15 (-OCH\({}_{2}\)CH\({}_{2}\)-), 50.78 (-OCH\({}_{2}\)CH\({}_{2}\)N\({}_{3}\)), 30.34 (C3) and 28.86 (C2). MS: \(m/z\) = 244.2 [M+H]\({}^{+}\). 2.3.2. 2-(-(2-(2-(Pent-4-en-1-yloxy)ethoxy)ethoxy)ethan-1-amine **20**  
Compound **19** (1153 mg, 4.73 mmol) was dissolved in THF (30 mL) and Ph\({}_{3}\)P (5.68 mmol) was added. The reaction was stirred at r.t. for 2 h, then 5.67 mmol of distilled water was added and the reaction was heated to 60 \({}^{\circ}\)C and stirred for 30 min, following the disappearance of the starting material observed by TLC (Hexane/EtOAc 8:2 and CH\({}_{2}\)Cl\({}_{2}\)/MeOH 9:1). The solvent was then evaporated and the crude purified by flash chromatography (silica gel, eluent: CH\({}_{2}\)Cl\({}_{2}\)/MeOH 9:1 to CH\({}_{2}\)Cl\({}_{2}\)/MeOH/NH\({}_{3}\) (aq) 7:3:1), affording amine **20** (0.951 g, 4.4 mmol, 93% yield). \({}^{1}\)H NMR (400 MHz, CD\({}_{3}\)OD) 8 5.83 (ddt, J = 13.5, 10.1, 6.7 Hz, 1H, H4), 5.02 (dd, J = 17.1, 1.1 Hz, 1H, H5a), 4.95 (d, J = 10.1 Hz, 1H, H5b), 3.69-3.53 (m, 12H, -OCH\({}_{2}\)CH\({}_{2}\)-), 3.52-3.45 (m, 2H, -OCH\({}_{2}\)CH\({}_{2}\)NH\({}_{2}\)), 2.12 (dd, J = 14.4, 7.2 Hz, 2H, H3a,b) and 1.72-1.58 (m, 2H, H2a,b). \({}^{13}\)C NMR (101 MHz, CD\({}_{3}\)OD) 8 139.44 (C4), 115.23 (C5), 73.67, 71.56, 71.50, 71.26, 71.12 and 70.39 (C1, -OCH\({}_{2}\)CH\({}_{2}\)-), 41.42 (-OCH\({}_{2}\)CH\({}_{2}\)NH\({}_{2}\)), 31.33 (C3) and 30.03 (C2). MS: \(m/z\) = 218.3 [M+H]\({}^{+}\). 2.3.3. (9H-Fluoren-9-yl)methyl-(S)-(3,7-dioxo-1,1,1-triphenyl-11,14,17-trioxa-2,8-diazadocos-21-en-6-yl) carbamate **21**  
Compound **20** (133 mg, 0.612 mmol) was dissolved in dry CH\({}_{2}\)Cl\({}_{2}\) (6 mL, 0.1 M) in argon atmosphere. The solution was cooled to 0 \({}^{\circ}\)C and Fmoc-L-Gln(Trt)-OH (0.64 mmol), HOBt (0.918 mmol) and EDC (0.918 mmol) were added. The reaction was warmed to r.t. and stirred under argon. After 15 h, TLC (CH\({}_{2}\)Cl\({}_{2}\)/MeOH 9:5:0.5 and CH\({}_{2}\)Cl\({}_{2}\)/MeOH/NH\({}_{3}\) (aq) 9:1:0.1) indicated the absence of the starting compound; the reaction was diluted with CH\({}_{2}\)Cl\({}_{2}\) and washed with water (3\(\times\)). The organic phase was collected, dried over sodium sulphate, filtered and evaporated. The crude was purified by flash chromatography on Biotage System (silica gel, gradient CH\({}_{2}\)Cl\({}_{2}\) 100%-CH\({}_{2}\)Cl\({}_{2}\)/MeOH 9:3:0.7). A total of 390 mg (0.48 mmol) of compound **21** was obtained (79% yield).