Scoping the triphasic/PTC conditions for the Juliá–Colonna epoxidation reaction

A new, highly efficient procedure for the Juliá–Colonna epoxidation is reported. Based on the original triphasic protocol it is shown that the co-catalysis of the reaction with phase transfer catalysts results in a dramatic increase of reactivity and sometimes also in a higher enantiomeric excess of product. The required amount of polyamino acid can be significantly reduced under the new conditions, such that large scale industrial application of the method is now feasible.