Synthesis of (αR,βS)-epoxyketones by asymmetric epoxidation of chalcones with cinchona phase-transfer catalysts

An efficient method to synthetically produce optically enriched (αR,βS)-epoxyketones was developed using a quaternary ammonium salt derived from cinchona alkaloid as the chiral phase-transfer catalyst. (αR,βS)-Epoxyketones were prepared in high optical purities (91–99% ee) by the asymmetric epoxidation of 1,3-diarylenones with aqueous sodium hypochlorite in the presence of a hydrocinchonine-derived chiral phase-transfer catalyst bearing a 2,3,4-trifluorobenzyl group.