Asymmetric Synthesis of α,β-Epoxysulfones via Phase-Transfer Catalytic Darzens Reaction

Described is the asymmetric synthesis of α,β-epoxysulfones by the catalytic phase-transfer Darzens reaction of chloromethyl phenyl sulfone with various aromatic aldehydes in the presence of the cinchona alkaloid-derived chiral phase-transfer catalysts bearing N -2,3,4-trifluorobenzyl moiety. The trans -(α R ,β R )-epoxysulfones were obtained in good chemical yields (81–95%) with high enantioselectivities (up to 97% ee) in the presence of N -(2,3,4-trifluorobenzyl)quinidinium bromide.