Self-disproportionation of enantiomers of α-trifluoromethyl lactic acid amides via sublimation

Preparation of racemic and enantiomerically enriched α-trifluoromethyl lactic acid amide [NHPh, NH(4-Cl-C6H5), NHBn, NHt-Bu] derivatives have been developed. Ph, 4-Cl-C6H5, and tert-Bu derivatives were found to have substantial magnitude of the self-disproportionation of enantiomers (SDE) via sublimation. For example, when the optically enriched Ph, 4-Cl-C6H5, and tert-Bu amide derivatives were subjected to sublimation under kinetic conditions (Petri dish in open air), the enantiomeric excess of the remainder has noticeably increased. On the other hand, the SDE of Bn amide derivative by sublimation resulted in almost no change in the optical purity of the remainder. These preliminary results on the SDE of the compounds under study, as well as their excellent chemical and physico-chemical characteristics, render these amide derivatives as readily available and very promising substrates for systematic study of SDE via sublimation.

N-Phenyl-, N-(4-Cl-C6H5)-, and N-tert-Bu-α-trifluoromethyl lactic acid amides were found to strongly exhibit the phenomenon of self-disproportionation of enantiomers (SDE) via sublimation. The results described in this paper support the hypothesis that compounds containing –CF3 group directly bonded to a stereogenic carbon center can induce a SDE effect.Figure optionsDownload as PowerPoint slide