The Electrophilic Thiocyanation/Cyclization Reaction of Allenic Acids: One-Step Preparation of Thiocyanated 2(5H)-furanones

Using electrophilic thiocyanating reagents as the thiocyanogen source, a series of 4-thiocyanato-2(5H)-furanones was rapidly synthesized in one step via electrophilic thiocyanation cyclization under Lewis acid catalysis, with the highest yield reaching 94%. This reaction proceeds under mild conditions without oxidants or metal reagents and is compatible with various substituents. It not only provides a new method for the preparation of 2(5H)-furanones but also offers a novel route for the synthesis of sulfur-containing 2(5H)-furanone derivatives.