Cu-Catalyzed Stereoselective Reaction of Allylic Carbonates with Diboronate

Significance

Allylboron derivatives are important synthetic intermediates, for instance, for the ste­reoselective allylation of carbonyl compounds. This is a new and very attractive method for a dia­stereoselective preparation of allylboron pinacolates, starting from readily available chiral allylic carbonates. The reaction conditions are extremely mild, and this process offers an excellent tolerance of functional groups. In the presence of ­Xanthphos as a ligand, the reaction is completely γ-selective. As expected, (Z)- and (E)-allylic carbonates with the same configuration of the chiral center give the opposite enantiomers of the product.