Site-selective Synthesis of 1,3-Dioxin-3-ones via a Gold(I) Catalyzed Cascade Reaction

A novel gold(I)-catalyzed protocol for the synthesis of 4H-1,3-dioxin-3-ones is presented. The protocol exploits a metal induced cascade sequence involving a [3,3]-sigmatropic rearrangement followed by regioselective O-annulation reactions. A wide range of oxygen-based heterocyclic scaffolds (21 examples) were achieved in excellent yield (up to 80%) and a detailed computation as well as deuterium-labelling investigations enabled all the plausible reaction pathways to be mapped and the rationalization of the recorded regioselectivity.