Asymmetric Oxidative Dimerization of the Enolates of N-[Bis(methylthio)methylene]- and N-(Diphenylmethylene)glycine Esters.

The oxidative dimerization of glycinates 1 with iodine takes place under kinetic control. The stereochemistry of the resulting 3-aminoaspartate 3 depends on the method used (base/solvent) to generate the corresponding enolate 2. Under suitable conditions, high yields and diastereomeric excesses in favor of the threo derivatives 3-I, which have C(2) symmetry, were obtained. In the presence of 8-phenylmenthol as chiral auxiliary (2S, 3S)-3-aminoaspartic acid 5-I was synthesized.