Application of Green Chiral Chromatography in Enantioseparation of Newly Synthesized Racemic Marinoepoxides.

Enantioseparation of the newly synthesized series of novel quinoline-2(1)-one epoxide structures -- and --, named marinoepoxides, is described. Marinoepoxide -, the key intermediate in the total synthesis of natural products marinoaziridines A and B, as well as their structural analogues, was synthesized by addition of the achiral ylide generated in situ from the sulfonium salt or , to the carbon-oxygen double bond of the corresponding quinoline-2(1)-one-4-carbaldehyde - in good yield. Separation of enantiomers of (±)-2,3,3-trisubstituted marinoepoxides -- and (±)--2,3-disubstituted marinoepoxides -- was studied using two immobilized polysaccharide type chiral stationary phases (CSPs); -(3,5-dichlorophenylcarbamoyl)cellulose stationary phase (CHIRAL ART Cellulose-SC) and (3,5-dimethylphenylcarbamoyl)amylose stationary phase (CHIRAL ART Amylose-SA). Enantioseparation conditions were explored by high-performance liquid chromatography (HPLC) using dimethyl carbonate/alcohol mixtures and -hexane/ethanol (80/20, /) as mobile phase, and by supercritical fluid chromatography (SFC) using CO/alcohol mixtures as mobile phase. In all examined racemates, enantioseparation was successfully achieved, but its efficiency largely depended on the structure of chiral selector and type/composition of the mobile phase.