Juliá–Colonna stereoselective epoxidation of some α,β-unsaturated enones possessing a stereogenic centre at the γ-position: synthesis of a protected galactonic acid derivative

Abstract

The oxidation of enones 6–8 using peroxide or percarbonate and polyleucines as catalysts gave the corresponding diastereomers 9–12 in high yield. The compound 9 was converted into the galactonic acid derivative 16 in five steps and in an overall yield of nearly 60%. Polyleucines are shown to be catalysts powerful enough to overturn the intrinsic stereocontrol in the chosen substrates.

p