Polyamino acids

The polyamino acid catalysed asymmetric epoxidation of chalcones, discovere d by Julia and Colonna ct al., provides the epoxides in excellent yields an d enantioselectivities, but the long reaction times lead to degradation of the polymer.(1,3). Lantos et al, used the triphasic polyamino acid catalysed epoxidation for t he synthesis of the leukotriene antagonist SK&F 104353 in 82% yield and 95% ec. After Baeyer-Villiger oxidation, recrystallisation and highly regiosel ective opening of the epoxide with methyl 3-mercaptopropionate, the target molecule was obtained in >99.5% ee.(5). Roberts et al. described the preparation of diltiazem, a blood pressure low ering agent starting from a simple enone precursor via a similar epoxidatio n/Baeyer-Villiger oxidation/epoxide opening protocol.(6).