1: With benzotriazol-1-ol; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride in dichloromethane T=20°C; 0.5 h; 2: With sodium tetrahydroborate; cerium(III) chloride; water in tetrahydrofuran T=0°C; 0.5 h;