Enantiomer self-disproportionation of chiral compounds on achiral ordered mesoporous silica M41S and regular silica gel as a stationary phase.

V J Mayani, S H R Abdi, R I Kureshy, N H Khan, S Agrawal, R V Jasra

Index: Chirality 21(2) , 255-61, (2009)

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Abstract

Chromatographic behavior of nonracemic mixtures, viz., mandelic acid and stilbene oxide as analytes has been studied in detailed by enantiomer self-disproportionation on achiral ordered mesoporous material M41S and regular silica gel as stationary phases. Enantiomer self-disproportionation gave enhanced separation of analytes. The extent and magnitude of enantiomer self-disproportionation is dependent on the optical purity of the starting non-racemic molecules, presence of intermolecular hydrogen bonding/pi-pi interactions and the nature of eluents used. The present study and previous literature data suggest that percentage ee of a nonracemic mixture needs to be determined before any chromatographic purification is taken up as enantiomer self-disproportionation phenomenon could occur during purification. The data show that enantiomer self-disproportionation of nonracemic mixtures can be harnessed for its enantioenrichment on inexpensive achiral stationary phases.(c) 2008 Wiley-Liss, Inc.