Enantio‐ and Diastereoselective Synthesis of <i>exo</i>‐Peroxyacetals: An Organocatalyzed Peroxyhemiacetalization/oxa‐Michael Addition Cascade

Abstract

Abstract An unprecedented enantioselective peroxyhemiacetalization/oxa‐Michael addition cascade of ortho ‐formyl homochalcones has been developed using cinchona‐alkaloid‐based chiral bifunctional organocatalysts to provide cis ‐configured exo ‐peroxyacetals, a new class of organic peroxide, in good yields with excellent enantio‐ and diastereoselectivities. The resulting cis ‐configured exo ‐peroxyacetals were converted into the corresponding trans ‐configured peroxyacetals without affecting the enantioselectivity. Furthermore, the displacement of the peroxide moiety of exo ‐peroxyacetals with various nucleophiles has been demonstrated to afford 1,3‐disubstituted isochromans with high diastereoselectivities and excellent enantioselectivities.