for the following products
3-O-tert-Butyl 4-O-methyl (4S)-2,2-dimethyl-1,3-oxazolidine-3,4-dicarboxylate | Boc-2,2-Dimethyloxazolidine-4-carboxylic acid methyl ester | Methyl (S)-(-)-3-Boc-2,2-dimethyl-4-oxazolidinecarboxylate and (S)-(-)-3-tert-Butoxycarbonyl-4-methoxycarbonyl-2,2-dimethyl-1,3-oxazolidine
