## 2 Experimental Section
### Preparation of Catalysts
#### 2.2.2 Immobilization of NHPI by Ester Bond Using (Chloromethyl) Polystyrene Resin  
Synthesis of AMPS-OCO-NHPI-1  
First, 22 mmol of trimellitic anhydride and 55 mmol of triethylamine were added to 1 g of Merrifield resins (chloromethyl)polystyrene (AMPS-Cl) pre-swelled in 30 mL of 1,4-dioxene. The reaction was carried out under reflux for 48 h. The resulting product was separated by filtration, and washed at 50 \({}^{\circ}\)C with H\({}_{2}\)O, MeOH, THF, and DCM. After drying under vacuum, immobilized anhydride was added to 110 mL of pyridine:DCE mixture (3:1, _v/v_) followed by addition of 55 mmol of hydroxylamine hydrochloride. The mixture was allowed to react for 24 h at 75 \({}^{\circ}\)C, under stirring. The product AMPS-OCO-NHPI-1 was filtered and washed at room temperature with H\({}_{2}\)O, H\({}_{2}\)O:MeOH (1:1, _v/v_) and at 50 \({}^{\circ}\)C with MeOH, DMF, THF, and DCM and then dried under vacuum. A total of 1.66 g of AMPS-OCO-NHPI-1 was obtained. Merrifield resin (AMPS-Cl) and NHPI immobilized by ester bond (AMPS-OCO-NHPI-1) were characterized by FTIR. Elemental analysis of AMPS-Cl and AMPS-OCO-NHPI-1 was performed and used for NHPI loading calculation.  
AMPS-Cl (Acros Organics): loading 5.5 mmol Cl/g, macroporous, 16-50 mesh, 5.5% DVB, IR: 3008, 2913, 1615, 1512, 1447, 1418, 1263, 1211, 1175, 1114, 1017, 908, 825, 745, 705 cm\({}^{-1}\); found: C 73.19%, H 7.29%.  
AMPS-OCO-NHPI-1: loading 2.1 mmol NHPI/g, IR: 3425, 2944, 1722, 1615, 1515, 1457, 1365, 1270, 1230, 1179, 1105, 1070, 1000, 824, 748, 711 cm\({}^{-1}\); found: C 68.75%, H 5.50%, N 2.89%.  
Synthesis of BMPS-OCO-NHPI-2  
First, 12.8 mmol of trimellitic anhydride and 32 mmol of triethylamine were added to 1 g of polystyrene (BMPS-Cl) pre-swelled in 25 mL 1,4-dioxane Merrifield resins (chloromethyll) and kept under reflux for 48 h. The resulting product was separated by filtration and washed at 50 \({}^{\circ}\)C with H\({}_{2}\)O, MeOH, THF, and DCM. After drying under vacuum, immobilized anhydride was added to 65 mL of pyridine:DCE mixture (3:1, _v/v_) followed by addition of 32 mmol of hydroxylamine hydrochloride. The mixture was allowed to react for 24 h at 75 \({}^{\circ}\)C, under stirring. The product BMPS-OCO-NHPI-2 was filtrated and washed at room temperature with H\({}_{2}\)O, H\({}_{2}\)O:MeOH (1:1, _v/v_) and at 50 \({}^{\circ}\)C with MeOH, DMF, THF, and DCM, and then dried under vacuum. A total of 1.30 g of BMPS-OCO-NHPI-2 was obtained. Merrifield resin (BMPS-Cl) and NHPI immobilized by ester bond (BMPS-OCO-NHPI-2) were characterized by FTIR. Elemental analysis of BMPS-Cl and BMPS-OCO-NHPI-2 was performed and used for NHPI loading calculation.  
BMPS-Cl (Acros Organics): loading 2.8-3.2 mmol Cl/g, microporous, 200-400 mesh, 2% DVB, IR: 3020, 2912, 1604, 1508, 1494, 1450, 1417, 1267, 1115, 1107, 904, 814, 764, 705, 675 cm\({}^{-1}\). Found: C 81.47%, H 7.88%.  
BMPS-OCO-NHPI-2: loading 0.9 mmol NHPI/g IR: 3460, 3017, 2934, 1721, 1614, 1508, 1489, 1474, 1357, 1269, 1240, 1180, 1115, 1061, 1015, 951, 812, 749, 701 cm\({}^{-1}\); found: C 73.39%, H 5.93%, N 1.28%.  
The loading of NHPI in APS-NHCO-NHPI-1, AMPS-OCO-NHPI-1, and BMPS-OCO-NHPI-2 resins is slightly different in comparison with previous ones [20], as Table 1 highlights. Solid supports ((aminomethyll) polystyrene and (chloromethyll) polystyrene resins) were delivered by the same company, Acros Organics. However, it could be a different batch of product. However, the key issue regarding the NHPI loading, as has been carefully determined after each series of experiments, is to have the exact value of the incorporated NHPI.