1: 67 percent / tetrahydrofuran / 2 h / -78 °C 2: 99 percent / H2 / Pd on carbon / aq. ethanol / 6 h / 760 Torr 3: 99 percent / CF3COOH / methanol / 4 h / 0 °C 4: 81 percent / H5IO6 / CrO3 / acetonitrile; H2O / 0.5 h 5: 72 percent / KHCO3 / dimethylformamide / 20 °C 6: 38 percent / potassium bromide; potassium acetate; peracetic acid / acetic acid / 20 °C View Scheme

n-butyllithium in tetrahydrofuran

Amberlist IR-120 in methanol; water 20 h; Ambient temperature;

potassium carbonate T=0 - 23°C; 14 h; Inert atmosphere;

n-propyl-magnesium bromide in tetrahydrofuran T=0°C; 0.5 h;

n-butyllithium in tetrahydrofuran 1) -78 deg C, 30 min; 2) -15 deg C, 15 min;

1: (2-oxo-propyl)-phosphonic acid dimethyl ester With 4-Acetylaminobenzenesulfonyl Azide; potassium carbonate in chloroform T=0°C; Seyferth-Gilbert homologation; 48 h; 2: (4S)-2,2-dimethyl-4-formyl-3-oxazolidine-carboxylic acid tert-butyl ester With potassium carbonate in methanol; chloroform T=0°C; Seyferth-Gilbert homologation; 24 h;

n-butyllithium in tetrahydrofuran; hexane T=-78°C; Yields of byproduct given. Title compound not separated from byproducts;

1: 1.) PPh3, 2.) Et3N / 1) CH2Cl2, -20 deg C, 30 min; 2) CH2Cl2, -60 deg C, 30 min, rt, overnight 2: 79 percent / BuLi / tetrahydrofuran / 1) -78 deg C, 30 min; 2) -15 deg C, 15 min View Scheme

1: (4S)-2,2-Dimethyl-4-(N-methoxy-N-methylcarbamoyl)oxazolidin-3-carbonsaeure-(tert-butyl)ester With lithium aluminium tetrahydride in tetrahydrofuran T=20°C; 0.5 h; Inert atmosphere; 2: (1-Diazo-2-oxo-propyl)-phosphonic acid dimethyl ester in methanol T=0°C; 0.5 h; Inert atmosphere; 3: With potassium carbonate in methanol T=20°C; 15 h; Inert atmosphere;