Asymmetric Synthesis of [2.2.2]-Bicyclic Lactones via All-Carbon Inverse-Electron-Demand Diels-Alder Reaction.

In this paper, a new cycloaddition between α,β-unsaturated aldehydes and coumalates realized under dienamine activation has been described. The reaction proceeds regioselectively with the distal double bond of the dienamine system acting as electron-rich dienophile. It leads to the formation of biologically relevant [2.2.2]-bicyclic lactones. Their functionalization potential has been confirmed in selected, diastereoselective transformations.