A convenient access to γ-lactones from O-allyl-α-bromoesters using a one-pot ionic-radical-ionic sequence.

Cognac in the jar! An efficient one-pot sequence for the preparation of γ-lactones is described. Following reduction of α-bromo ester precursors with DIBAL-H and radical cyclization of the resulting O-aluminum acetals, a preparative in-situ Oppenauer-type oxidation of the cyclic O-aluminum acetal using simple aldehydes or ketones gives access to γ-lactones in high yields.