Atom-Economic Route to Densely Functionalized Thiophenes via Base-Catalyzed Rearrangement of 5-Propargyl-2<i>H</i>-thiopyran-4(3<i>H</i>)-ones

<div><p></p><p>An atom-economic route to densely functionalized thiophenes has been developed via base-catalyzed rearrangement of 5-propargyl-2<i>H</i>-thiopyran-4(3<i>H</i>)-ones involving tandem retro-thio Michael addition, propargyl isomerization, and intramolecular thio-addition to allenes.</p>