1: 4-Benzyl-2,5-dioxo-oxazolidine-3-carboxylic acid benzyl ester With ethanol; O-propargylquinidine in diethyl ether T=20°C; 0.25 h; Molecular sieve; 2: ethanol in diethyl ether T=-60°C; 20 h; Reagent/catalyst; enantioselective reaction;

1: 4-Benzyl-2,5-dioxo-oxazolidine-3-carboxylic acid benzyl ester With ethanol; O-propargylquinine in diethyl ether T=20°C; 0.25 h; Molecular sieve; 2: ethanol in diethyl ether T=-60°C; 20 h; Reagent/catalyst; enantioselective reaction;

4 A molecular sieve in diethyl ether T=-60°C; 17 h; Title compound not separated from byproducts.;

1: 4-Benzyl-2,5-dioxo-oxazolidine-3-carboxylic acid benzyl ester With ethanol; O-propargylquinidine in diethyl ether T=20°C; 0.25 h; Molecular sieve; 2: With ethanol in diethyl ether T=-60°C; 20 h; 3: methanol in diethyl ether T=20°C; 0.5 h; Reagent/catalyst; enantioselective reaction;

1: 4-Benzyl-2,5-dioxo-oxazolidine-3-carboxylic acid benzyl ester With ethanol; O-propargylquinine in diethyl ether T=20°C; 0.25 h; Molecular sieve; 2: ethanol in diethyl ether T=-60°C; 20 h; Reagent/catalyst; enantioselective reaction;