triethylamine in ethyl acetate T=70°C; 10 h; Inert atmosphere;

triethylamine in ethyl acetate 12 h; Reflux;

triethylamine in ethyl acetate 15 h; Heating;

triethylamine in tetrahydrofuran

1.1: L-phenylalanine; (1S)-10-camphorsulfonic acid / N,N-dimethyl-formamide / 20 - 70 °C / Inert atmosphere 2.1: toluene-4-sulfonic acid / benzene / 24 h / 80 °C / Inert atmosphere 3.1: ammonia; lithium / tetrahydrofuran / 1 h / -30 °C / Inert atmosphere 3.2: 3 h / Reflux 4.1: ozone / tetrahydrofuran / -78 °C / Inert atmosphere 4.2: 4 h / 25 °C / Inert atmosphere 5.1: 2,6-dimethylpyridine / dichloromethane / 1 h / -78 °C / Inert atmosphere 6.1: tetrapropylammonium perruthennate; 4-methylmorpholine N-oxide / dichloromethane / 18 h / 25 °C / Inert atmosphere 7.1: sodium hexamethyldisilazane / tetrahydrofuran / 0.5 h / 0 °C / Inert atmosphere 7.2: 15 h / 65 °C / Inert atmosphere 8.1: palladium 10 on activated carbon; hydrogen / methanol / 12 h / 3620.13 Torr / Inert atmosphere 9.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 12 h / 25 °C / Inert atmosphere 10.1: hydrogenchloride / tetrahydrofuran / 8 h / 20 °C / Inert atmosphere 11.1: sodium hexamethyldisilazane / tetrahydrofuran / 0.5 h / 0 °C / Inert atmosphere 11.2: 18 h / 25 °C / Inert atmosphere 12.1: rhodium(III) trichloride hydrate / ethanol / 18 h / Inert atmosphere; Reflux 13.1: tetrapropylammonium perruthennate; 4-methylmorpholine N-oxide / dichloromethane / 15 h / 25 °C / Inert atmosphere View Scheme

triethylamine; benzoic acid in xylene 22 h; Heating;

L-phenylalanine; (1S)-10-camphorsulfonic acid in N,N-dimethyl-formamide

hexamethylimidazolium hexafluorophosphate; D-(+)-Phenylalanine; (1S)-10-camphorsulfonic acid in N,N-dimethyl-formamide T=20 - 70°C; Title compound not separated from byproducts;