A question of policy: should tests for the self-disproportionation of enantiomers (SDE) be mandatory for reports involving scalemates?

Abstract

The self-disproportionation of enantiomers (SDE) is a phenomenon that can lead to the perturbation of the enantiomeric excess (ee) in fractions obtained from a scalemic sample that has been subjected to a physical process. While fractional crystallization is widely appreciated as a means to effect enantiopurification, processes that are potentially able to give rise to the SDE phenomenon, notably chromatography, are greatly underappreciated in this regard. In this exposition we question if sufficient care is being taken by workers to avoid the erroneous reporting of stereochemical outcomes in asymmetric synthesis, natural products work, and other chiral-based areas of study due to ignorance of the SDE phenomenon and recommend the incorporation of SDE tests via sublimation and achiral chromatography as outlined herein to check for the occurrence of the SDE phenomenon in the applied methodology and routine experimental work.