1 Stereocontrol by a pair of epimeric sugar-derived ligands of the coordination sphere of Cu(II) complexes Federico Cisnetti, Régis Guillot, Michel Thérisod, Michel Desmadril and Clotilde Policar Supplementary materials General methods Reagents and solvents were purchased from Acros and used without further purification. NMR was performed on Brucker DRX250 and AV360 spectrometers, IR spectra were recorded on a Brucker IFS66, ES-MS were recorded on a Finnigan Mat 95S in a BE configuration at low resolution. CHN Microanalyses have been recorded at the CNRS (Gif- sur-Yvette, France. Cyclic voltammetry was performed on an electronic Autolab potentiostat (working electrode: glassy carbon, counter electrode: Pt wire, reference electrode: SCE). EPR spectra were recorded on Brucker Elexis 500 spectrometer. Vis spectra were recorded on a Cary 300 bio spectrophotometer at 20°C. CD spectra were recorded on a Jasco J-710 spectropolarimeter at 20°C. Synthesis and characterization of ligands and intermediates H 2 , Pd/C quant. CHO N NaBH(OAc) 3 , DCE 2 O O O HO N 3 4 3 2 1 O O O O 5 N N N N O O O O NH 2 N O O O O N 3 N N Cl MeOH PTC 96% 1 2 3 L1 66% H 2 , Pd/C quant. CHO N NaBH(OAc) 3 , DCE 2 O O O HO N 3 4 3 2 1 O O O O 5 N N N N O O O O NH 2 N O O O O N 3 N N Cl MeOH PTC 98% 5 L2 64% 6 4 Scheme S1. Synthetic pathways to L1 and L2. 5-azido-5-deoxy-1,2-O-isopropylidene-3-O-(2-picolyl)--D-xylofuranose (2) 5-azido-5-deoxy-1,2-O-isopropylidene--D-xylofuranose (1, 1,29 g, 6 mmol, 1eq), tetrabutylammonium hydrogensulfate (191 mg, 0.6 mmol, 0.1 eq) and 2-picolyl chloride hydrochloride were dissolved in a biphasic mixture of toluene (15 mL) and water (5 mL). This mixture was vigorously stirred overnight. Then, 50 mL water and 50 mL dichloromethane were added and the organic phase was decanted. The aqueous phase was again extracted with 2*50 mL of dichloromethane. The joint organic phases were dried (Na 2 SO 4 ) and evaporated. 3 was obtained in a pure form after column chromatography (AcOEt/MeOH 9:1). Isolated mass: 1.22 g (yield: 66%) 1 H-NMR (250 MHz, CDCl 3 ): 8.53 (d (wide signals), 1H, 3 J 5py,6py = 4.8 Hz, H6py); 7.69 (ddd, 1H, 3 J 4py,5py = 3 J 3py,4py = 7.7 Hz, 4 J 4py,6py = 1.6 Hz, H4py); 7.37 (d, 1H, 3 J 3py,4py = 7.7 Hz, H3py); 7.19 (m, 1H, H5py); 5.92 (d, 1H, 3 J 1,2 = 3.7 Hz, H1); [4.78 (d, 1H, 2 J = 12.9 Hz), 4.65