Pd-Catalyzed Asymmetric Allylic Substitution Cascade of Substituted 4-Hydroxy-2 H -pyrones with meso -Allyl Dicarbonates.

An efficient Pd-catalyzed asymmetric allylic substitution cascade of 4-hydroxy-2 H -pyrones with meso -allyl dicarbonates has been developed for the synthesis of kinetic chiral tetrahydro-1 H -pyrano[4,3- b ]benzofuran-1-one products in ≤87% yield and ≤99% ee. The protocol was achieved via a temperature-controlled kinetic control process, which has been illustrated by means of the experimental results and control experiments. The reaction could be conducted on a gram scale, and the resulting product allows for several transformations.