Organocatalytic Asymmetric Kornblum-DeLaMare Rearrangement

The first asymmetric version of the base-catalyzed Kornblum-DeLaMare rearrangement has been developed and applied to the desymmetrization of meso-endoperoxides resulting in the synthesis of γ-hydroxyenones. Six- to eight-membered, differently substituted products are accessible in good to excellent enantiomeric ratios. As chiral catalysts, the authors employed a cinchona alkaloid derivative. They proposed that the modified quinidine acts as a bifunctional Brønsted base/Brønsted acid catalyst promoting the enantiodetermining deprotonation via an E2-elimination mechanism. Furthermore, an example of a one-pot variant starting from the 1,3-diene is reported.