Epoxy-annulations by reactions of α-amido ketones with vinyl sulfonium salts.: Reagent versus substrate control and kinetic resolution

Diphenyl vinyl sulfonium salt and chiral amido-ketones undergo highly diaslereoselective epoxy-annulation reactions in good yield. The use of a chiral vinyl sulfonium salt dominates the stereochemical outcome of the annulation reaction (reagent control is greater than substrate control), and this has allowed the kinetic resolution of racemic amido-ketones to be achieved.