A new chiral glycine synthon. Synthesis, x-ray structure of (−).(2S,4R)-2-ethoxycarbonyl-4-phenyl-1,3-oxazolidine and diastereoselective nucleophilic ring opening to (R)-ethyl α-amino carboxylates.
Condensation of (R)-N-benzyl-2-phenylglycinol 1 with the methyl hemiacetal of ethyl glyoxylate leads to (2S,4R)-2-ethoxycarbonyl-4-phenyl-1,3-oxazolidine 2 as the major product, obtained as a pure enantiomer after column chromatography. Compound 2 is stereoselectively cleaved by dialkylzinc reagents, prepared from alkylmagnesium iodides and ZnCl2, with moderate to good d.e.ś (72–94 %). These compounds