1: With (αS,βR)-α-amino-β-hydroxybutyric acid; magnesium sulfate in tetrahydrofuran; water T=20°C; 120 h; Sealed vial; 2: With water; ammonium chloride in tetrahydrofuran Saturated solution; optical yield given as percent eeenantioselective reaction;

water; (S, S)-6,6’-bis(1-hydroxy-2,2-dimethylpropyl)-2,2’-bipyridine; scandium tris(trifluoromethanesulfonate) in acetonitrile T=-20°C; 34 h; Title compound not separated from byproducts;

diproline-DPEN in tetrahydrofuran; water T=20°C; 20 h; optical yield given as percent ee;

water; O-TBDPS-proline T=20°C; 90 h;